Year	Tonnes
1950	3.667
1951	11.001
1952	7.334
1953	11.001
1954	7.334
1955	11.001
1956	11.001
1957	11.001
1958	11.001
1959	11.001
1960	14.668
1961	18.335
1962	18.335
1963	22.002
1964	22.002
1965	25.669
1966	29.336
1967	33.003
1968	36.67
1969	62.339
1970	66.006
1971	69.673
1972	77.007
1973	80.674
1974	73.34
1975	77.007
1976	84.341
1977	69.673
1978	99.009
1979	150.347
1980	113.677
1981	95.342
1982	113.677
1983	102.676
1984	113.677
1985	128.345
1986	132.012
1987	146.68
1988	165.015
1989	165.015
1990	161.348
1991	168.682
1992	201.685
1993	223.687
1994	260.357
1995	311.695
1996	326.363
1997	308.028
1998	308.028
1999	319.029
2000	330.03
2001	363.033
2002	326.363
2003	359.366
2004	355.699
2005	366.7
2006	366.7
2007	385.035
2008	396.036
2009	385.035
2010	403.37
2011	407.037
2012	407.037
2013	407.037
2014	407.037