(a) Second class counties.--The classes of magisterial districts in judicial districts coextensive with counties of the second class shall be determined as follows:

(1) Magisterial districts of the first class shall have a population density of more than 5,000 persons per square mile and a population of not less than 65,000 persons.

(2) Magisterial districts of the second class shall have a population density of more than 500 persons per square mile and a population of between 22,500 and 65,000 persons.

(3) Magisterial districts of the third class shall have a population density of more than 200 persons per square mile and a population of between 12,000 and 22,500 persons.

(4) Magisterial districts of the fourth class shall have a population density of more than 70 persons per square mile and a population of between 7,500 and 12,000 persons.

(5) Magisterial districts of the fifth class shall have a population density of less than 70 persons per square mile and a population of between 4,000 and 7,500 persons.

(b) Other counties.--The classes of magisterial districts in judicial districts not coextensive with counties of the first class or counties of the second class shall be determined as follows:

(1) Magisterial districts of the first class shall have a population density of more than 1,000 persons per square mile and a population of not less than 15,000 persons.

(2) Magisterial districts of the second class shall have a population density of more than 400 persons per square mile and a population of not less than 4,000 persons.

(3) Magisterial districts of the third class shall have a population density of less than 400 persons per square mile and a population of not less than 4,000 persons.

(4) Magisterial districts of the fourth class shall have a population density of less than 400 persons per square mile and a population of between 2,000 and 4,000 persons. The number of magisterial districts of the fourth class within a judicial district shall not be increased.