Year	kt
1960	2860.26
1961	3652.332
1962	5045.792
1963	6505.258
1964	9431.524
1965	10912.992
1966	12383.459
1967	15192.381
1968	17572.264
1969	22526.381
1970	25434.312
1971	29629.36
1972	31004.485
1973	32797.648
1974	35115.192
1975	34235.112
1976	35309.543
1977	37022.032
1978	39625.602
1979	35789.92
1980	30960.481
1981	32566.627
1982	39434.918
1983	39284.571
1984	36028.275
1985	36809.346
1986	38202.806
1987	36299.633
1988	34315.786
1989	34623.814
1990	25078.613
1991	17040.549
1992	14502.985
1993	26761.766
1994	16021.123
1995	17733.612
1996	14774.343
1997	11727.066
1998	12203.776
1999	11397.036
2000	10546.292
2001	10553.626
2002	11943.419
2003	12042.428
2004	11386.035
2005	12929.842
2006	13296.542
2007	12750.159
2008	12123.102
2009	11587.72
2010	11155.014
2011	10348.274
2012	10923.993
2013	10007.243
2014	11015.668
2015	11829.742
2016	12218.444