Okla. Stat. tit. 60, § 701

All Postal Savings System accounts created by the deposits of persons whose last-known addresses are in this state which have not been claimed by the persons entitled thereto before May 1, 1971, are presumed to have been abandoned by their owners and are declared to escheat and become the property of this state. Laws 1971, c. 41, § 1, emerg. eff. March 25, 1971.