To the extent practicable, the head of each agency shall provide that the obligation of not less than 10 percent of the total combined amounts obligated for contracts and subcontracts by each agency under this Act and amendments made by this Act pursuant to competitive procedures within the meaning of either the Federal Property and Administrative Services Act of 1949 (
41 U.S.C.
251 et seq.), or chapter
137 of title
10, shall be expended either with—