Year	Tonnes
1928	33.003
1929	29.336
1930	22.002
1931	22.002
1932	14.668
1933	14.668
1934	14.668
1935	18.335
1936	25.669
1937	33.003
1938	40.337
1939	36.67
1992	23879.504
1993	19508.44
1994	19042.731
1995	17520.926
1996	18349.668
1997	18107.646
1998	16310.816
1999	15159.378
2000	14858.684
2001	15570.082
2002	14888.02
2003	17124.89
2004	17282.571
2005	16754.523
2006	16175.137
2007	18709.034
2008	17491.59
2009	14565.324
2010	18107.646
2011	18606.358
2012	17623.602
2013	19893.475
2014	19519.441