Year	kt
1960	13384.55
1961	11327.363
1962	13655.908
1963	12449.465
1964	13652.241
1965	13967.603
1966	14616.662
1967	15504.076
1968	15493.075
1969	16688.517
1970	18129.648
1971	19090.402
1972	19915.477
1973	21503.288
1974	21844.319
1975	25845.016
1976	25808.346
1977	27810.528
1978	29075.643
1979	30172.076
1980	29702.7
1981	30832.136
1982	32610.631
1983	28980.301
1984	30663.454
1985	30703.791
1986	31646.21
1987	31866.23
1988	33512.713
1989	33666.727
1990	30850.471
1991	27612.51
1992	19963.148
1993	19086.735
1994	20564.536
1995	24722.914
1996	26164.045
1997	23652.15
1998	23322.12
1999	23465.133
2000	24081.189
2001	23582.477
2002	24238.87
2003	23450.465
2004	22852.744
2005	23721.823
2006	23545.807
2007	22647.392
2008	24770.585
2009	25089.614
2010	31158.499
2011	26541.746
2012	26835.106
2013	25041.943
2014	24524.896
2015	26079.704
2016	25254.629