Year	kt
1960	5262.145
1961	5727.854
1962	5991.878
1963	6365.912
1964	7025.972
1965	7568.688
1966	7748.371
1967	8657.787
1968	9493.863
1969	10861.654
1970	11081.674
1971	12838.167
1972	15320.726
1973	16208.14
1974	17234.9
1975	17997.636
1976	19255.417
1977	19328.757
1978	18500.015
1979	20784.556
1980	22493.378
1981	22959.087
1982	25071.279
1983	25547.989
1984	24711.913
1985	21862.654
1986	22335.697
1987	21660.969
1988	22064.339
1989	28653.938
1990	28334.909
1991	29211.322
1992	33263.357
1993	31110.828
1994	31015.486
1995	34279.116
1996	33391.702
1997	34906.173
1998	39698.942
1999	40520.35
2000	38551.171
2001	40340.667
2002	42493.196
2003	38455.829
2004	38283.48
2005	39706.276
2006	34884.171
2007	34183.774
2008	33127.678
2009	31114.495
2010	29266.327
2011	26494.075
2012	23835.5
2013	24279.207
2014	24290.208
2015	24777.919
2016	26006.364