Year	kt
1960	1012.092
1961	927.751
1962	957.087
1963	1349.456
1964	1719.823
1965	2343.213
1966	3201.291
1967	4136.376
1968	5331.818
1969	6373.246
1970	6270.57
1971	7000.303
1972	7656.696
1973	9050.156
1974	9578.204
1975	11041.337
1976	13527.563
1977	14194.957
1978	15511.41
1979	16622.511
1980	17916.962
1981	18342.334
1982	19116.071
1983	18606.358
1984	19163.742
1985	18195.654
1986	19303.088
1987	19163.742
1988	18965.724
1989	19310.422
1990	20414.189
1991	20241.84
1992	17795.951
1993	19149.074
1994	19339.758
1995	21011.91
1996	23446.798
1997	22236.688
1998	22390.702
1999	22684.062
2000	22115.677
2001	24532.23
2002	24759.584
2003	27223.808
2004	26824.105
2005	27700.518
2006	26241.052
2007	24517.562
2008	24187.532
2009	20960.572
2010	22482.377
2011	21422.614
2012	19185.744
2013	17645.604
2014	15991.787
2015	17154.226
2016	18386.338