(1) The valuation for assessment of all taxable property in the state shall be twenty-nine percent of the actual value thereof as determined by the assessor and the administrator in the manner prescribed by law, and such percentage shall be uniformly applied, without exception, to the actual value, so determined, of the various classes and subclasses of real and personal property located within the territorial limits of the authority levying a property tax, and all property taxes shall be levied against the aggregate valuation for assessment resulting from the application of such percentage. This subsection (1) shall not apply to residential real property, producing mines, and lands or leaseholds producing oil or gas.

(1.5) Residential real property shall be valued for assessment at twenty-one percent of its actual value, except as provided in section 39-1-104.2.

(2) Repealed.

(3) "Valuation for assessment", as used in this section and in articles 1 to 13 of this title, means the same as the term "assessed valuation" as that term may appear in the laws of this state.

(4) Except as provided in section 39-7-109, nonproducing severed mineral interests are to be valued at twenty-nine percent of actual value in the same manner as other real property. Such valuation shall be determined by the assessing officer only upon preponderant evidence shown by such officer that the cost approach, market approach, and income approach result in uniform and just and equal valuation.

(5) to (10.1) Repealed.

(10.2)

(a) Except as otherwise provided in subsection (12) of this section, beginning with the property tax year which commences January 1, 1989, a reassessment cycle shall be instituted with each cycle consisting of two full calendar years. At the beginning of each reassessment cycle, the level of value to be used during the reassessment cycle in the determination of actual value of real property in any county of the state as reflected in the abstract of assessment for each year in the reassessment cycle shall advance by two years over what was used in the previous reassessment cycle; except that the level of value to be used for the years 1989 and 1990 shall be the level of value for the period of one and one-half years immediately prior to July 1, 1988; except that, if comparable valuation data is not available from such one-and-one-half-year period to adequately determine the level of value for a class of property, the period of five years immediately prior to July 1, 1988, shall be utilized to determine the level of value. Said level of value shall be adjusted to the final day of the data gathering period.

(b) During the two years of each reassessment cycle, in preparation for implementation in the succeeding reassessment cycle, the respective assessors shall conduct revaluations of all taxable real property utilizing the level of value for the period which will be used to determine actual value in such succeeding reassessment cycle and the manuals and associated data published for the period which will be used to determine actual value in such succeeding reassessment cycle.

(c) Repealed.

(d) For the purposes of this article and article 9 of this title, "level of value" means the actual value of taxable real property as ascertained by the applicable factors enumerated in section 39-1-103 (5) for the one-and-one-half-year period immediately prior to July 1 immediately preceding the assessment date for which the administrator is required by this article to publish manuals and associated data. Beginning with the property tax year commencing January 1, 1999, if comparable valuation data is not available from such one-and-one-half-year period to adequately determine such actual value for a class of property, "level of value" means the actual value of taxable real property as ascertained by said applicable factors for such one-and-one-half-year period, the six-month period immediately preceding such one-and-one-half-year period, and as many preceding six-month periods within the five-year period immediately prior to July 1 immediately preceding the assessment date as are necessary to obtain adequate comparable valuation data. Said level of value shall be adjusted to the final day of the data-gathering period.

(e) Repealed.

(10.3) Repealed.

(11)

(a)

(I) It is the intent of the general assembly, as manifested in subsection (10.2) of this section, that, when a change occurs in reassessment cycles as prescribed in said subsection, new manuals and associated data will be published by the administrator, pursuant to section 39-2-109 (1)(e), and that said manuals and associated data and the level of value for the year that said manuals and associated data are published shall be utilized by assessors in the manner described in subsection (10.2) of this section for determining the actual value of real property in each county of the state.

(II) The general assembly hereby further finds and declares that it is the intent of paragraph (b) of this subsection (11) to comply with the provisions of section 3 of article X of the state constitution, including the provision which requires the enactment of "general laws, which shall prescribe such methods and regulations as shall secure just and equalized valuations for assessments of all real and personal property"; to reduce the confusion of the owners of taxable property within the state concerning assessment procedures and valuations of such property; to achieve valuations for assessment which represent the current value of such property to the extent which is equitably and practically possible; and to minimize the costs associated with achieving such current valuations for assessment.

(b)

(I) The provisions of subsection (10.2) of this section are not intended to prevent the assessor from taking into account, in determining actual value for the years which intervene between changes in the level of value, any unusual conditions in or related to any real property which would result in an increase or decrease in actual value. If any real property has not been assessed at its correct level of value, the assessor shall revalue such property for the intervening year so that the actual value of such property will be its correct level of value; however, the assessor shall not revalue such property above or below its correct level of value except as necessary to reflect the increase or decrease in actual value attributable to an unusual condition. For the purposes of this paragraph (b) and except as otherwise provided in this paragraph (b), an unusual condition which could result in an increase or decrease in actual value is limited to the installation of an on-site improvement, the ending of the economic life of an improvement with only salvage value remaining, the addition to or remodeling of a structure, a change of use of the land, the creation of a condominium ownership of real property as recognized in the "Condominium Ownership Act", article 33 of title 38, C.R.S., any new regulations restricting or increasing the use of the land, or a combination thereof, the installation and operation of surface equipment relating to oil and gas wells on agricultural land, any detrimental acts of nature, and any damage due to accident, vandalism, fire, or explosion. When taking into account such unusual conditions which would increase or decrease the actual value of a property, the assessor must relate such changes to the level of value as if the conditions had existed at that time.

(II) The creation of a condominium ownership of real property by the conversion of an existing structure shall be taken into account as an unusual condition as provided for in subparagraph (I) of this paragraph (b) by the assessor, when at least fifty-one percent of the condominium units, as defined in section 38-33-103 (1), C.R.S., in a multiunit property subject to condominium ownership have been sold and conveyed to bona fide purchasers and deeds have been recorded therefor.

(c) Repealed.

(12)

(a) For the property tax years commencing on or after January 1, 1987, producing mines shall be valued for assessment solely pursuant to article 6 of this title.

(b) For the property tax years commencing on or after January 1, 1987, oil and gas leaseholds and lands shall be valued for assessment solely pursuant to section 39-7-102.

(c) Repealed.

(12.1) Repealed.

(12.2)

(a) Except as provided in subsection (12) of this section, for property tax years commencing on or after January 1, 1987, the requirement stated in subsections (10.2) and (11) of this section that the actual value of real property be determined according to a specified year's level of value and manuals and associated data published by the administrator for said specified year pursuant to section 39-2-109 (1)(e) shall apply to the assessment of all classes of real property, including but not limited to the following classes of real property:

(I) (Deleted by amendment, L. 87, p. 1390, § 2, effective April 1, 1987.)

(II) (Deleted by amendment, L. 87, p. 1392, § 2, effective April 1, 1987.)

(III) Operating property and plants of public utilities; and

(IV) Agricultural land.

(V) (Deleted by amendment, L. 87, p. 1385, § 1, effective June 20, 1987.)

(b) This subsection (12.2) shall take effect January 1, 1987.

(12.3)

(a)

(I) The actual value of personal property shall be determined by appropriate consideration of such of the three approaches specified in section 39-1-103 (5)(a) as are applicable to the appraisal of such property. Subject to review and approval pursuant to section 39-2-109 (1)(e), the administrator shall prepare and publish appraisal procedures and instructions for the annual appraisal of such property that will include a factor or factors to adjust the actual value for the current year of assessment to the level of value applicable to real property.

(II) In determining actual value, depreciation attributable to age shall not exceed that for the actual age of the property on the assessment date. Physical, functional, and economic obsolescence shall be considered in determining actual value.

(b) Repealed.

(12.4) For property tax years commencing on and after January 1, 1987, the requirement stated in subsections (10.2) to (11) of this section that the actual value of real property be determined according to a specified year's level of value and manuals and associated data published by the administrator for said specified year pursuant to section 39-2-109 (1)(e) shall not apply to the assessment of producing coal mines and other lands producing nonmetallic minerals.

(13) to (15) Repealed.

(16)

(a) During each property tax year, the director of research of the legislative council shall contract with a private person for a valuation for assessment study to be conducted as set forth in this subsection (16). The study shall be conducted in all counties of the state to determine whether or not the assessor of each county has, in fact, used all manuals, formulas, and other directives required by law to arrive at the valuation for assessment of each and every class of real and personal property in the county. The person conducting the study shall sample each class of property in a statistically valid manner, and the aggregate of such sampling shall equal at least one percent of all properties in each county of the state. The sampling shall show that the various areas, ages of buildings, economic conditions, and uses of properties have been sampled. Such study shall be completed, and a final report of the findings and conclusions thereof shall be submitted to the state board of equalization, by September 15 of the year in which the study is conducted.

(b) During each property tax year, beginning with the property tax year which commences January 1, 1985, in addition to the requirements set forth in paragraph (a) of this subsection (16), the study shall set forth the aggregate valuation for assessment of each county for the year in which the study is conducted.

(c) The person conducting any valuation for assessment study pursuant to this subsection (16) and his employees shall, during the term of his contract, have access to any document in the custody of the administrator or an assessor, including, but not limited to, such documents as are held pursuant to sections 39-4-103, 39-5-120, and 39-14-102 (1)(c). The penalties in section 39-1-116 apply against the divulging at any time of any confidential information obtained pursuant to this paragraph (c).

(d) Repealed.