Wash. Rev. Code § 48.14.021
As to premiums received from policies or contracts issued in connection with a pension, annuity or profit-sharing plan exempt or qualified under sections 401, 403(b), 404, 408(b), or 501(a) of the United States internal revenue code, the rate of tax specified in RCW 48.14.020 shall be reduced twelve and one-half percent with respect to the tax payable in 1964, twenty-five percent with respect to the tax payable in 1965, thirty-seven and one-half percent with respect to the tax payable in 1966, fifty percent with respect to the tax payable in 1967, sixty-two and one-half percent with respect to the tax payable in 1968, seventy-five percent with respect to the tax payable in 1969, eighty-seven and one-half percent with respect to the tax payable in 1970, and one hundred percent with respect to the tax payable in 1971 and annually thereafter.
RCW 48.14.021