Year	kt
1960	3120.617
1961	3285.632
1962	3300.3
1963	4374.731
1964	4939.449
1965	6380.58
1966	6310.907
1967	6318.241
1968	6659.272
1969	8001.394
1970	5705.852
1971	6695.942
1972	6970.967
1973	8500.106
1974	8998.818
1975	11364.033
1976	13413.886
1977	13802.588
1978	11936.085
1979	13556.899
1980	12841.834
1981	14286.632
1982	15566.415
1983	19182.077
1984	20623.208
1985	23765.827
1986	24367.215
1987	26552.747
1988	29119.647
1989	31433.524
1990	31741.552
1991	30571.779
1992	32089.917
1993	32155.923
1994	33344.031
1995	33010.334
1996	31239.173
1997	33655.726
1998	35126.193
1999	33714.398
2000	35588.235
2001	36644.331
2002	35401.218
2003	35129.86
2004	35885.262
2005	35298.542
2006	33292.693
2007	34887.838
2008	32797.648
2009	33296.36
2010	31011.819
2011	31136.497
2012	32122.92
2013	27564.839
2014	26413.401
2015	22130.345
2016	17238.567