Year Millions Of Dollars 1918 30579.0 1919 36408.0 1920 36217.0 1921 28177.0 1922 30480.0 1923 33619.0 1924 33466.0 1925 35202.0 1926 34963.0 1927 34824.0 1928 34678.0 1929 36252.0 1930 29695.0 1931 23748.0 1932 19097.0 1933 21013.0 1934 22402.0 1935 24195.0 1936 26935.0 1937 29504.0 1938 27487.0