Year	kt
1960	20018.153
1961	21554.626
1962	25426.978
1963	28008.546
1964	30183.077
1965	33516.38
1966	36042.943
1967	39625.602
1968	41950.48
1969	46053.853
1970	49284.48
1971	52628.784
1972	54586.962
1973	57597.569
1974	64099.16
1975	70006.697
1976	76387.277
1977	74165.075
1978	76643.967
1979	74044.064
1980	76889.656
1981	80806.012
1982	81147.043
1983	80743.673
1984	68792.92
1985	68587.568
1986	70366.063
1987	68202.533
1988	67351.789
1989	66629.39
1990	66050.004
1991	54502.621
1992	48543.746
1993	46666.242
1994	42507.864
1995	44066.339
1996	44473.376
1997	36504.985
1998	34319.453
1999	31448.192
2000	31330.848
2001	30186.744
2002	31213.504
2003	33736.4
2004	31921.235
2005	31888.232
2006	32518.956
2007	29229.657
2008	27850.865
2009	24231.536
2010	24708.246
2011	25434.312
2012	24682.577
2013	22533.715
2014	21411.613
2015	20425.19
2016	20630.542