Year	Tonnes
1931	3.667
1932	11.001
1933	14.668
1934	11.001
1935	14.668
1936	29.336
1937	62.339
1938	62.339
1939	58.672
1940	22.002
1941	22.002
1942	55.005
1943	36.67
1944	18.335
1945	18.335
1946	22.002
1947	25.669
1948	25.669
1949	29.336
1950	414.371
1951	381.368
1952	476.71
1953	513.38
1954	579.386
1955	1646.483
1956	2005.849
1957	1983.847
1958	2170.864
1959	2229.536
1960	3223.293
1961	3065.612
1962	3204.958
1963	3611.995
1964	4367.397
1965	3678.001
1966	4917.447
1967	4609.419
1968	5962.542
1969	7242.325
1970	6659.272
1971	8885.141
1972	7766.706
1973	7895.051
1974	9666.212
1975	11184.35
1976	13758.584
1977	14664.333
1978	15221.717
1979	22548.383
1980	20802.891
1981	26637.088
1982	24488.226
1983	27960.875
1984	33091.008
1985	29651.362
1986	31352.85
1987	36226.293
1988	36945.025
1989	34565.142
1990	37359.396
1991	42529.866
1992	42918.568
1993	45665.151
1994	46647.907
1995	41664.454
1996	42804.891
1997	40960.39
1998	50274.57
1999	52372.094
2000	51040.973
2001	48778.434
2002	39064.551
2003	54275.267
2004	51103.312
2005	50626.602
2006	53582.204
2007	66468.042
2008	67681.819
2009	62331.666
2010	61605.6
2011	56908.173
2012	44730.066
2013	36438.979
2014	30703.791