Year	kt
1960	1576.81
1961	1818.832
1962	1958.178
1963	1650.15
1964	1536.473
1965	1624.481
1966	1899.506
1967	1917.841
1968	2185.532
1969	2222.202
1970	2482.559
1971	2940.934
1972	4085.038
1973	3498.318
1974	2423.887
1975	2456.89
1976	2654.908
1977	2948.268
1978	3285.632
1979	3777.01
1980	1573.143
1981	3498.318
1982	3146.286
1983	3131.618
1984	2948.268
1985	2757.584
1986	2871.261
1987	2823.59
1988	2577.901
1989	4099.706
1990	2174.531
1991	2229.536
1992	1415.462
1993	1481.468
1994	1606.146
1995	1774.828
1996	1756.493
1997	1411.795
1998	1628.148
1999	2790.587
2000	2845.592
2001	3127.951
2002	3641.331
2003	3894.354
2004	3762.342
2005	3916.356
2006	3545.989
2007	3380.974
2008	3799.012
2009	3417.644
2010	3494.651
2011	3777.01
2012	3157.287
2013	3333.303
2014	3861.351
2015	3340.637
2016	3362.639