SECTION 801. In addition to other taxes, there shall be levied, collected, and paid upon the income of every individual a tax equal to the following percentages of the wages (as defined in section 811) received by him after December 31, 1936, with respect to employment (as defined in section 811) after such date:
(1) With respect to employment during the calendar years 1937, 1938, and 1939, the rate shall be 1 per centum.
(2) With respect to employment during the calendar years 1940, 1941, and 1942, the rate shall 1 « per centum.
(3) With respect to employment during the calendar years 1943, 1944, and 1945, the rate shall be 2 per centum.
(4) With respect to employment during the calendar years 1946, 1947, and 1948, the rate shall be 2 « per centum.
(5) With respect to employment after December 31, 1948, the rate shall be 3 per centum.