Effective January 1, 1974, this state or any of its agencies or boards may elect to become liable for payments in lieu of contributions for a period of not less than three consecutive taxable years by filing a written notice of its election with the department not later than thirty days after written notice that such election may be made is first given to the employing unit by the department. This election is extended to the state hospitals and institutions of higher education that were subject to this chapter prior to January 1, 1974, without regard to the length of time their present method of financing has been in force.