Year kt 1960 0 1961 0 1962 0 1963 0 1964 0 1965 0 1966 0 1967 0 1968 0 1969 0 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 29.336 1984 216.353 1985 1287.117 1986 2130.527 1987 2706.246 1988 3171.955 1989 3615.662 1990 4162.045 1991 4712.095 1992 4954.117 1993 5610.51 1994 6270.57 1995 7260.66 1996 8555.111 1997 9006.152 1998 9783.556 1999 10285.935 2000 10190.593 2001 10604.964 2002 10597.63 2003 10674.637 2004 10612.298 2005 10076.916 2006 10388.611 2007 9303.179 2008 9328.848 2009 8921.811 2010 10128.254 2011 8514.774 2012 7979.392 2013 7594.357 2014 6420.917 2015 6534.594 2016 6593.266