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 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 231.021 1991 223.687 1992 245.689 1993 289.693 1994 480.377 1995 432.706 1996 418.038 1997 462.042 1998 469.376 1999 465.709 2000 443.707 2001 473.043 2002 429.039 2003 487.711 2004 2739.249 2005 3168.288 2006 4587.417 2007 5511.501 2008 6241.234 2009 7066.309 2010 5240.143 2011 1998.515 2012 1510.804 2013 1870.17 2014 619.723 2015 4008.031 2016 6985.635