Year	kt
1960	3212.292
1961	3755.008
1962	4506.743
1963	5181.471
1964	5859.866
1965	6541.928
1966	7135.982
1967	8118.738
1968	8272.752
1969	9468.194
1970	10828.651
1971	13520.229
1972	13600.903
1973	14976.028
1974	15086.038
1975	14488.317
1976	14576.325
1977	15361.063
1978	16494.166
1979	17583.265
1980	16226.475
1981	14579.992
1982	12603.479
1983	11675.728
1984	11778.404
1985	11386.035
1986	13560.566
1987	12163.439
1988	10747.977
1989	10439.949
1990	12933.509
1991	13175.531
1992	13157.196
1993	13538.564
1994	15394.066
1995	15515.077
1996	16395.157
1997	17836.288
1998	19970.482
1999	22599.721
2000	21939.661
2001	23498.136
2002	22999.424
2003	22115.677
2004	23461.466
2005	22376.034
2006	22159.681
2007	23157.105
2008	21360.275
2009	21048.58
2010	20054.823
2011	17586.932
2012	16780.192
2013	17253.235
2014	16794.86
2015	17645.604
2016	18687.032