There is hereby created on the books of the Treasury of the United States a trust fund to be known as the “Federal Hospital Insurance Trust Fund” (hereinafter in this section referred to as the “Trust Fund”). The Trust Fund shall consist of such gifts and bequests as may be made as provided in section
401
(i)(1) of this title, and such amounts as may be deposited in, or appropriated to, such fund as provided in this part. There are hereby appropriated to the Trust Fund for the fiscal year ending June 30, 1966, and for each fiscal year thereafter, out of any moneys in the Treasury not otherwise appropriated, amounts equivalent to 100 per centum of—
The amounts appropriated by the preceding sentence shall be transferred from time to time from the general fund in the Treasury to the Trust Fund, such amounts to be determined on the basis of estimates by the Secretary of the Treasury of the taxes, specified in the preceding sentence, paid to or deposited into the Treasury; and proper adjustments shall be made in amounts subsequently transferred to the extent prior estimates were in excess of or were less than the taxes specified in such sentence.