Year	Tonnes
1968	3667
1981	11001
1982	14668
1983	18335
1984	22002
1985	25669
1986	29336
1987	33003
1988	40337
1989	47671
1990	55005
1991	62339
1992	69673
1993	80674
1994	91675
1995	102676
1996	113677
1997	124678
1998	135679
1999	146680
2000	157681
2001	168682
2002	179683
2003	190684
2004	201685
2005	212686
2006	223687
2007	234688
2008	245689
2009	256690
2010	267691
2011	278692
2012	289693
2013	300694
2014	311695