(As amended Jan. 21, 1963, eff. July 1, 1963; Feb. 28, 1966, eff. July 1, 1966; Apr. 29, 1980, eff. Aug. 1, 1980; Pub. L. 97–462, § 2, Jan. 12, 1983, 96 Stat. 2527, eff. Feb. 26, 1983; Mar. 2, 1987, eff. Aug. 1, 1987; Apr. 22, 1993, eff. Dec. 1, 1993; Apr. 17, 2000, eff. Dec. 1, 2000; Apr. 30, 2007, eff. Dec. 1, 2007; Apr. 29, 2015, eff. Dec. 1, 2015; Apr. 28, 2016, eff. Dec. 1, 2016; Apr. 27, 2017, eff. Dec. 1, 2017.)