Year Thousands Of Short Tons 1905 3.50000 1906 3.80000 1907 26.4000 1908 19.6000 1909 11.2000 1910 23.2000 1911 9.00000 1912 4.50000 1913 40.7000 1914 20.0000 1915 14.2000 1916 17.5000 1917 53.7000 1918 41.2000 1919 36.8000 1920 71.0000 1921 70.3000 1922 16.8000 1923 27.8000 1924 20.8000 1925 13.1000 1926 26.9000 1927 53.5000 1928 48.4000 1929 85.9000 1930 167.300 1931 143.600 1932 128.200 1933 110.500 1934 124.800 1935 90.5000 1936 55.5000 1937 79.1000 1938 157.500 1939 83.7000 1940 19.2000