Section effective July 1, 1971, pursuant to Resolution No. 71–9 of the Board of Governors. See section 15(a) of Pub. L. 91–375, set out as a note preceding section 101 of this title.

Pub. L. 109–435, title V, § 505(c), Dec. 20, 2006, 120 Stat. 3236, provided that: “Nothing in this Act [see Tables for classification] or any amendment made by this Act shall affect any free mailing privileges accorded under section 3217 or sections 3403 through 3406 of title 39, United States Code.”