Year	kt
1960	40832.045
1961	40333.333
1962	42295.178
1963	43556.626
1964	38158.802
1965	35272.873
1966	32489.62
1967	29757.705
1968	27333.818
1969	24187.532
1970	18819.044
1971	13080.189
1972	10351.941
1973	10340.94
1974	11078.007
1975	8522.108
1976	9233.506
1977	9794.557
1978	11019.335
1979	11727.066
1980	12706.155
1981	14730.339
1982	12849.168
1983	20271.176
1984	25283.965
1985	25280.298
1986	23402.794
1987	25536.988
1988	28353.244
1989	30619.45
1990	29889.717
1991	27557.505
1992	27803.194
1993	27638.179
1994	30223.414
1995	32973.664
1996	31752.553
1997	29266.327
1998	29060.975
1999	25646.998
2000	25415.977
2001	24642.24
2002	28485.256
2003	29618.359
2004	28906.961
2005	28023.214
2006	27124.799
2007	26593.084
2008	26673.758
2009	24821.923
2010	25309.634
2011	27410.825
2012	30168.409
2013	29658.696
2014	33259.69
2015	40619.359
2016	37836.106