Year	Tonnes
1950	286.026
1951	311.695
1952	388.702
1953	432.706
1954	407.037
1955	348.365
1956	484.044
1957	462.042
1958	447.374
1959	385.035
1960	491.378
1961	491.378
1962	550.05
1963	601.388
1964	674.728
1965	847.077
1966	993.757
1967	876.413
1968	1037.761
1969	1147.771
1970	1250.447
1971	1529.139
1972	1763.827
1973	2046.186
1974	1906.84
1975	2038.852
1976	2086.523
1977	2614.571
1978	2922.599
1979	2794.254
1980	2464.224
1981	2251.538
1982	2086.523
1983	2104.858
1984	2002.182
1985	2266.206
1986	2607.237
1987	2757.584
1988	2940.934
1989	2973.937
1990	2955.602
1991	3336.97
1992	3791.678
1993	3953.026
1994	5269.479
1995	4866.109
1996	4748.765
1997	4987.12
1998	5317.15
1999	5522.502
2000	5474.831
2001	5760.857
2002	6325.575
2003	6626.269
2004	6930.63
2005	6868.291
2006	7099.312
2007	8122.405
2008	8129.739
2009	7902.385
2010	7568.688
2011	7741.037
2012	7766.706
2013	7598.024
2014	7759.372