(a) The basic foundation allowance to the county for professional educators is the amount of money required to pay the state minimum salaries, in accordance with provisions of article four, chapter eighteen-a of this code, subject to the following:

(1) In making this computation a county shall receive an allowance for state aid eligible professional educator positions to each one thousand students in net enrollment as follows:

(A) For each high-density county, seventy-two and three tenths professional educators per each one thousand students in net enrollment;

(B) For each medium-density county, seventy-two and forty-five one hundredths professional educators per each one thousand students in net enrollment;

(C) For each low-density county, seventy-two and six tenths professional educators per each one thousand students in net enrollment;

(D) For each sparse-density county, seventy-two and seventy-five one hundredths professional educators per each one thousand students in net enrollment; and

(E) For any professional educator positions, or fraction thereof, determined for a county pursuant to paragraphs (A), (B), (C) and (D) of this subdivision that exceed the number employed, the county’s allowance for these positions shall be determined using the average state funded salary of professional educators for the county;

(2) The number of and the allowance for personnel paid in part by state and county funds shall be prorated; and

(3) Where two or more counties join together in support of a vocational or comprehensive high school or any other program or service, the professional educators for the school or program may be prorated among the participating counties on the basis of each one's enrollment therein and the personnel shall be considered within the above-stated limit.

(b) Each county board shall establish and maintain a minimum ratio of professional instructional personnel per state aid funded professional educators as follows:

(1) For each high-density county, the minimum ratio of professional instructional personnel per state aid funded professional educators, or the number employed, whichever is less, is ninety-one and twenty-nine one hundredths percent;

(2) For each medium-density county, the minimum ratio of professional instructional personnel per state aid funded professional educators, or the number employed, whichever is less, is ninety-one and twenty-four one hundredths percent;

(3) For each low-density county, the minimum ratio of professional instructional personnel per state aid funded professional educators, or the number employed, whichever is less, is ninety-one and eighteen one hundredths percent;

(4) For each sparse-density county, the minimum ratio of professional instructional personnel per state aid funded professional educators, or the number employed, whichever is less, is ninety-one and seven one hundredths percent; and

(5) Where two or more counties join together in support of a vocational or comprehensive high school or any other program or service, the professional instructional personnel for the school or program may be prorated among the participating counties on the basis of each one's enrollment therein and the personnel shall be considered within the above-stated limit.

(c) Any county board which does not establish and maintain the applicable minimum ratio required in subsection (b) of this section shall suffer a pro rata reduction in the allowance for professional educators under this section: Provided, That a county may not be penalized if it has increases in enrollment during that school year. Provided, however, That for the school year 2017-2018, only, a county may not be penalized for not meeting the applicable minimum ratio required in subsection (b) of this section.

(d) A county may not increase the number of administrative personnel employed as either professional educators or pay grade "H" service personnel above the number which were employed, or for which positions were posted, on June 30, 1990, and, therefore, county boards shall whenever possible utilize classroom teachers for curriculum administrative positions through the use of modified or extended contracts.