The provisions of this part to the extent that they relate to the Unemployment Trust Fund in the Treasury of the United States, shall be operative only so long as such Unemployment Trust Fund continues to exist and so long as the Secretary of the Treasury of the United States of America continues to maintain for this state a separate book account of all funds deposited therein by this state for benefit purposes, together with this state's proportionate share of the earnings of such Unemployment Trust Fund, from which no other state is permitted to make withdrawals.