Year	kt
1960	2970.27
1961	2786.92
1962	2893.263
1963	3263.63
1964	4041.034
1965	3329.636
1966	4598.418
1967	4305.058
1968	5500.5
1969	6574.931
1970	5845.198
1971	8030.73
1972	6893.96
1973	7102.979
1974	8833.803
1975	10278.601
1976	12277.116
1977	13028.851
1978	13413.886
1979	20806.558
1980	19020.729
1981	24532.23
1982	22233.021
1983	25195.957
1984	29966.724
1985	26519.744
1986	28360.578
1987	29101.312
1988	30054.732
1989	27440.161
1990	28404.582
1991	32130.254
1992	31400.521
1993	32775.646
1994	32870.988
1995	32441.949
1996	33230.354
1997	32625.299
1998	34532.139
1999	36061.278
2000	34869.503
2001	34334.121
2002	22984.756
2003	37660.09
2004	34018.759
2005	35463.557
2006	38276.146
2007	51382.004
2008	52962.481
2009	45225.111
2010	39874.958
2011	38048.792
2012	29002.303
2013	23582.477
2014	19061.066
2015	18760.372
2016	19754.129