This subpart is derived in part from one or more provisions of Act 24 of the extra session of the Legislature of 1936-1937, approved January 26, 1937 (Acts 1936-37, p. 20); Act 512 of the Regular Session of the Legislature of 1939, approved September 21, 1939 (Acts 1939, p. 795); subdivision 10 of Article 16 of Chapter 4 of Title 62 of the 1949 Code of Alabama (Title 62, p. 322); Act 334 of the Regular Session of the Legislature of 1945, approved July 6, 1945 (Loc. Acts 1945, p. 144); Act 237 of the Regular Session of the Legislature of 1947, approved August 4, 1947 (Loc. Acts 1947, p. 144); Act 470 of the Regular Session of the Legislature of 1949, approved August 25, 1949; Act 1272, 1973 Regular Session (Acts 1973, p. 2124); Act 791, 1975 Regular Session (Acts 1975, p. 1585); Act 94-567, 1994 Regular Session (Acts 1994, p. 1039); Act 96-635, 1996 Regular Session (Acts 1996, p. 1008); Act 99-307, 1999 Regular Session (Acts 1999, p. 415); Act 2000-558, 2000 Regular Session (Acts 2000, p. 773); Act 2001-544, 2001 Special Session (Acts 2001, p. 1095); Act 2001-563, 2001 Special Session (Acts 2001, p. 1140); and Act 2002-438, 2002 Regular Session (Acts 2002, p. 1145), and other amendatory acts for the pension system, as amended; but nothing in the derivation of this subpart or in the above statement of derivation shall be construed to render this subpart other than an act original in form. This subpart shall apply to Class 1 cities of the State of Alabama which have the requisite population according to the last, any preceding, or any succeeding federal census, and shall only apply to Class 1 municipalities according to such census.