Year	Tonnes
1951	3.667
1952	7.334
1953	3.667
1954	3.667
1955	3.667
1956	3.667
1957	3.667
1958	7.334
1959	11.001
1960	11.001
1961	11.001
1962	11.001
1963	14.668
1964	14.668
1965	14.668
1966	14.668
1967	22.002
1968	22.002
1969	18.335
1970	25.669
1971	25.669
1972	25.669
1973	25.669
1974	29.336
1975	29.336
1976	29.336
1977	25.669
1978	25.669
1979	33.003
1980	36.67
1981	36.67
1982	40.337
1983	40.337
1984	44.004
1985	47.671
1986	47.671
1987	47.671
1988	55.005
1989	58.672
1990	58.672
1991	58.672
1992	58.672
1993	62.339
1994	66.006
1995	80.674
1996	73.34
1997	80.674
1998	77.007
1999	80.674
2000	102.676
2001	110.01
2002	102.676
2003	117.344
2004	113.677
2005	117.344
2006	113.677
2007	154.014
2008	132.012
2009	132.012
2010	139.346
2011	128.345
2012	135.679
2013	132.012
2014	135.679