Year	kt
1960	267.691
1961	278.692
1962	289.693
1963	300.694
1964	337.364
1965	311.695
1966	344.698
1967	458.375
1968	502.379
1969	572.052
1970	619.723
1971	737.067
1972	773.737
1973	803.073
1974	865.412
1975	1041.428
1976	942.419
1977	1386.126
1978	1826.166
1979	1584.144
1980	3652.332
1981	5082.462
1982	6076.219
1983	6281.571
1984	6054.217
1985	6472.255
1986	1991.181
1987	1840.834
1988	1910.507
1989	7326.666
1990	366.7
1991	-161.348
1992	2471.558
1993	2629.239
1994	2647.574
1995	2977.604
1996	3468.982
1997	2904.264
1998	2838.258
1999	2654.908
2000	2988.605
2001	2933.6
2002	2951.935
2003	3322.302
2004	3443.313
2005	3197.624
2006	3362.639
2007	4576.416
2008	4330.727
2009	5588.508
2010	5687.517
2011	5302.482
2012	4880.777
2013	3736.673
2014	5298.815
2015	6182.562
2016	5969.876