Year kt 1960 5995.545 1961 8096.736 1962 11741.734 1963 14106.949 1964 4345.395 1965 13171.864 1966 11327.363 1967 2027.851 1968 -726.066 1969 1565.809 1970 278.692 1971 344.698 1972 1026.76 1973 1653.817 1974 1752.826 1975 2049.853 1976 4389.399 1977 4228.051 1978 5284.147 1979 4341.728 1980 6505.258 1981 11023.002 1982 10395.945 1983 9875.231 1984 15746.098 1985 16241.143 1986 20003.485 1987 15159.378 1988 16435.494 1989 15848.774 1990 22137.679 1991 13435.888 1992 21037.579 1993 33384.368 1994 39310.24 1995 35063.854 1996 30326.09 1997 35133.527 1998 32115.586 1999 35954.935 2000 31305.179 2001 36306.967 2002 38829.863 2003 37326.393 2004 38958.208 2005 44924.417 2006 45918.174 2007 48096.372 2008 54407.279 2009 61799.951 2010 60054.459 2011 52236.415 2012 64124.829 2013 58312.634 2014 51737.703 2015 51378.337 2016 54685.971