Year	Tonnes
1972	22.002
1973	51.338
1974	88.008
1975	187.017
1976	594.054
1977	781.071
1978	832.409
1979	942.419
1980	986.423
1981	1008.425
1982	1100.1
1983	1030.427
1984	1045.095
1985	1158.772
1986	1067.097
1987	1239.446
1988	1301.785
1989	1430.13
1990	2702.579
1991	2636.573
1992	2779.586
1993	3197.624
1994	3032.609
1995	3047.277
1996	2757.584
1997	2801.588
1998	3344.304
1999	3160.954
2000	3780.677
2001	3850.35
2002	3978.695
2003	3828.348
2004	3898.021
2005	4096.039
2006	4136.376
2007	4231.718
2008	4506.743
2009	3762.342
2010	4686.426
2011	4176.713
2012	4231.718
2013	5229.142
2014	7033.306