Year Kilotonnes 1850 0.00002 1851 0.00002 1852 0.00004 1853 0.00006 1854 0.00008 1855 0.0001 1856 0.00012 1857 0.00014 1858 0.00016 1859 0.00019 1860 0.00021 1861 0.00041 1862 0.00061 1863 0.00082 1864 0.00102 1865 0.00122 1866 0.00143 1867 0.00163 1868 0.00184 1869 0.00204 1870 0.00225 1871 0.00245 1872 0.00266 1873 0.00287 1874 0.00309 1875 0.0033 1876 0.00351 1877 0.00372 1878 0.00394 1879 0.00415 1880 0.00436 1881 0.00494 1882 0.0046 1883 0.00463 1884 0.00466 1885 0.00513 1886 0.0056 1887 0.00607 1888 0.00656 1889 0.00729 1890 0.0077 1891 0.00649 1892 0.00837 1893 0.00731 1894 0.00909 1895 0.00803 1896 0.00903 1897 0.01017 1898 0.01052 1899 0.01061 1900 0.01268 1901 0.01381 1902 0.02762 1903 0.04143 1904 0.05523 1905 0.06904 1906 0.08285 1907 0.09666 1908 0.1105 1909 0.1243 1910 0.1381 1911 1.989 1912 5.674 1913 14.86 1914 20.37 1915 25.91 1916 42.43 1917 52.1 1918 38.07 1919 43.96 1920 36.32 1921 58.46 1922 79.8 1923 106.6 1924 156.4 1925 163 1926 145.3 1927 157.1 1928 198.1 1929 226.4 1930 242.4 1931 206.8 1932 93.33 1933 115 1934 186.5 1935 182 1936 164.5 1937 252.9 1938 208 1939 205.5 1940 245.8 1941 265.7 1942 268.6 1943 253.7 1944 263.5 1945 254.6 1946 230.5 1947 240.1 1948 245.6 1949 224.9 1950 274.8 1951 297.9 1952 318.7 1953 330.8 1954 335.6 1955 347.7 1956 369.9 1957 353.9 1958 401.2 1959 415 1960 405.2 1961 400.3 1962 360.9 1963 364.8 1964 376.6 1965 408.7 1966 406 1967 407.6 1968 498 1969 439.8 1970 459.5 1971 475.5 1972 460.3 1973 507.5 1974 533.6 1975 461.8 1976 368.2 1977 384.3 1978 351.7 1979 358 1980 340.9 1981 323.9 1982 296.7 1983 332.2 1984 305.4 1985 294.7 1986 280 1987 277.4 1988 283.3 1989 265.9 1990 247.4 1991 200.4 1992 156.9 1993 164.7 1994 163 1995 176.1 1996 183.6 1997 161.1 1998 166.8 1999 168.7 2000 153.5