Year	kt
1960	2922.599
1961	3091.281
1962	3241.628
1963	3380.974
1964	3523.987
1965	3424.978
1966	3674.334
1967	3520.32
1968	3747.674
1969	4675.425
1970	5676.516
1971	6563.93
1972	7088.311
1973	7627.36
1974	8280.086
1975	8115.071
1976	9270.176
1977	9424.19
1978	9809.225
1979	9768.888
1980	9292.178
1981	8826.469
1982	8551.444
1983	8690.79
1984	9728.551
1985	10410.613
1986	9255.508
1987	9640.543
1988	9237.173
1989	10058.581
1990	11994.757
1991	12680.486
1992	12449.465
1993	13131.527
1994	13505.561
1995	14748.674
1996	15698.427
1997	15130.042
1998	15529.745
1999	15801.103
2000	15082.371
2001	15984.453
2002	15911.113
2003	17176.228
2004	17590.599
2005	18518.35
2006	17337.576
2007	16336.485
2008	17297.239
2009	16879.201
2010	18602.691
2011	17557.596
2012	16780.192
2013	16171.47
2014	14759.675
2015	15749.765
2016	16450.162