Year	kt
1960	36519.653
1961	39057.217
1962	39577.931
1963	43948.995
1964	48045.034
1965	45885.171
1966	44253.356
1967	39064.551
1968	38536.503
1969	37337.394
1970	46200.533
1971	42251.174
1972	40461.678
1973	40025.305
1974	38587.841
1975	37157.711
1976	37520.744
1977	36802.012
1978	38078.128
1979	37759.099
1980	36677.334
1981	37722.429
1982	38650.18
1983	37025.699
1984	36868.018
1985	36537.988
1986	35507.561
1987	35808.255
1988	32977.331
1989	30916.477
1990	24095.857
1991	23696.154
1992	20546.201
1993	19138.073
1994	18635.694
1995	18213.989
1996	18661.363
1997	18081.977
1998	16739.855
1999	16274.146
2000	15144.71
2001	14051.944
2002	14172.955
2003	14682.668
2004	13355.214
2005	11998.424
2006	12185.441
2007	12405.461
2008	12141.437
2009	10087.917
2010	10846.986
2011	11030.336
2012	10637.967
2013	9339.849
2014	8800.8
2015	9295.845
2016	8870.473