Okla. Stat. tit. 8, § 9
Benevolent, religious and charitable institutions which own, maintain and operate cemeteries under the laws of this state shall be permitted to retain ten percent (10%) of the gross proceeds of all lots sold by such an institution for the purpose of interment; and any sum so retained may be used by it in any manner which may further its legitimate objects.
Laws 1910-11, SB 27, c. 17, p. 34, § 1.