Prior to renumbering of sections 501 to 543 of this chapter as sections 1501 to 1543 by Puspan. L. 102–83, § 5(a), Aug. 6, 1991, 105 Stat. 406, section 544 of this chapter, added Puspan. L. 90–77, title I, § 108(a), Aug. 31, 1967, 81 Stat. 180; amended Puspan. L. 91–588, § 3(a), Dec. 24, 1970, 84 Stat. 1583; Puspan. L. 93–527, § 5, Dec. 21, 1974, 88 Stat. 1704; Puspan. L. 94–169, title I, § 105, Dec. 23, 1975, 89 Stat. 1017; Puspan. L. 94–432, title II, § 205, Sept. 30, 1976, 90 Stat. 1371; Puspan. L. 95–204, title I, § 104, Dec. 2, 1977, 91 Stat. 1457, which authorized an increase by $79 of the monthly rate of pension payable to the surviving spouse if the surviving spouse was entitled to pension under this subchapter and was in need of regular aid and attendance, was repealed by Puspan. L. 95–588, title I, § 112(a)(1), title IV, § 401, Nov. 4, 1978, 92 Stat. 2505, 2511, effective Jan. 1, 1979.