Year	kt
1960	649.059
1961	773.737
1962	1199.109
1963	1727.157
1964	2079.189
1965	2478.892
1966	2834.591
1967	3138.952
1968	3461.648
1969	3817.347
1970	4085.038
1971	4206.049
1972	4396.733
1973	4895.445
1974	4323.393
1975	3872.352
1976	4165.712
1977	4140.043
1978	4180.38
1979	3780.677
1980	2977.604
1981	2874.928
1982	2852.926
1983	2731.915
1984	2673.243
1985	2893.263
1986	3164.621
1987	3600.994
1988	3678.001
1989	4081.371
1990	4407.734
1991	5196.139
1992	5375.822
1993	5383.156
1994	5284.147
1995	4737.764
1996	4862.442
1997	4979.786
1998	5133.8
1999	5386.823
2000	5852.532
2001	6208.231
2002	6296.239
2003	6831.621
2004	7781.374
2005	8140.74
2006	7686.032
2007	7524.684
2008	7576.022
2009	7058.975
2010	7403.673
2011	7697.033
2012	7466.012
2013	7348.668
2014	7003.97
2015	6761.948
2016	6611.601