Year	Tonnes
1952	3.667
1953	3.667
1954	3.667
1955	11.001
1956	11.001
1957	11.001
1958	11.001
1959	11.001
1960	11.001
1961	14.668
1962	14.668
1963	14.668
1964	18.335
1965	25.669
1966	25.669
1967	33.003
1968	36.67
1969	36.67
1970	40.337
1971	47.671
1972	55.005
1973	66.006
1974	66.006
1975	58.672
1976	62.339
1977	80.674
1978	62.339
1979	110.01
1980	102.676
1981	135.679
1982	121.011
1983	143.013
1984	143.013
1985	150.347
1986	154.014
1987	161.348
1988	157.681
1989	161.348
1990	146.68
1991	146.68
1992	143.013
1993	143.013
1994	139.346
1995	143.013
1996	143.013
1997	143.013
1998	143.013
1999	150.347
2000	150.347
2001	157.681
2002	157.681
2003	161.348
2004	161.348
2005	161.348
2006	165.015
2007	179.683
2008	187.017
2009	194.351
2010	198.018
2011	198.018
2012	198.018
2013	201.685
2014	201.685