Year	kt
1960	3010.607
1961	2823.59
1962	3105.949
1963	2691.578
1964	2922.599
1965	3336.97
1966	3281.965
1967	3193.957
1968	3175.622
1969	3604.661
1970	3589.993
1971	3465.315
1972	3087.614
1973	2698.912
1974	3263.63
1975	3003.273
1976	3402.976
1977	2658.575
1978	2933.6
1979	3670.667
1980	3828.348
1981	3571.658
1982	3593.66
1983	3593.66
1984	4363.73
1985	4448.071
1986	3964.027
1987	3766.009
1988	3744.007
1989	3700.003
1990	3274.631
1991	2977.604
1992	2911.598
1993	3226.96
1994	3744.007
1995	3887.02
1996	3817.347
1997	3898.021
1998	4066.703
1999	4030.033
2000	3982.362
2001	3578.992
2002	3080.28
2003	2995.939
2004	3516.653
2005	2948.268
2006	2698.912
2007	3054.611
2008	3259.963
2009	2126.86
2010	2907.931
2011	3208.625
2012	3098.615
2013	2940.934
2014	3223.293
2015	3113.283
2016	2874.928