Section, added Pub. L. 89–722, § 1(b)(1), Nov. 2, 1966, 80 Stat. 1152; amended Pub. L. 93–625, § 4(c)(1), Jan. 3, 1975, 88 Stat. 2111; Pub. L. 94–455, title VI, § 605(b), Oct. 4, 1976, 90 Stat. 1575; Pub. L. 99–514, title VIII, § 805(c)(1)(A), Oct. 22, 1986, 100 Stat. 2362, included increase in vacation pay suspense account in gross income.