In this section, “constitutional officer” means: the Attorney General of the State; the Comptroller of the State; the Lieutenant Governor of the State; the Secretary of State; or the Treasurer of the State. A constitutional officer who is a member of the Employees’ Pension System: on taking office, has immediate vesting rights in the Employees’ Pension System; and except as provided in paragraph (2) of this subsection, is entitled to a retirement allowance as provided in Title 23, Subtitle 4 of this article. The retirement allowance of a constitutional officer who serves at least one full term may not be less than 10% of the annual salary received during the constitutional officer's last term.