Year	kt
1970	3.667
1971	3.667
1972	3.667
1973	3.667
1974	3.667
1975	3.667
1976	3.667
1977	7.334
1978	11.001
1979	18.335
1980	18.335
1981	25.669
1982	29.336
1983	29.336
1984	51.338
1985	62.339
1986	55.005
1987	58.672
1988	62.339
1989	62.339
1990	80.674
1991	80.674
1992	77.007
1993	84.341
1994	88.008
1995	102.676
1996	124.678
1997	121.011
1998	128.345
1999	135.679
2000	146.68
2001	161.348
2002	168.682
2003	187.017
2004	198.018
2005	212.686
2006	220.02
2007	223.687
2008	216.353
2009	242.022
2010	311.695
2011	366.7
2012	440.04
2013	443.707
2014	443.707
2015	458.375
2016	480.377