Year	kt
1960	495.045
1961	506.046
1962	550.05
1963	575.719
1964	634.391
1965	616.056
1966	612.389
1967	689.396
1968	744.401
1969	770.07
1970	821.408
1971	894.748
1972	964.421
1973	1070.764
1974	1162.439
1975	1195.442
1976	1294.451
1977	1393.46
1978	1668.485
1979	1745.492
1980	1877.504
1981	2002.182
1982	2079.189
1983	2192.866
1984	894.748
1985	2365.215
1986	2405.552
1987	2614.571
1988	2687.911
1989	2456.89
1990	2456.89
1991	1862.836
1992	1749.159
1993	1642.816
1994	1096.433
1995	1019.426
1996	1151.438
1997	1125.769
1998	1213.777
1999	1199.109
2000	1316.453
2001	1488.802
2002	1430.13
2003	1565.809
2004	1727.157
2005	1686.82
2006	1950.844
2007	2398.218
2008	2555.899
2009	2328.545
2010	2471.558
2011	3069.279
2012	3479.983
2013	3674.334
2014	3391.975
2015	3366.306
2016	3050.944