(g) Unless authorized to continue by a two-thirds vote of the members elected to each house, this section and the bond insurance program authorized by this section expire on the sixth anniversary of the date on which this section becomes a part of the constitution. However, bond insurance issued before the expiration of this section and the program is not affected by the expiration of this section and the program and remains in effect according to its terms, and the state is required to fulfill all of the terms of that previously issued insurance.