Year kt 1960 1807.831 1961 1884.838 1962 2544.898 1963 2918.932 1964 3219.626 1965 3446.98 1966 4767.1 1967 5203.473 1968 6413.583 1969 7161.651 1970 3920.023 1971 4052.035 1972 4789.102 1973 5361.154 1974 5713.186 1975 6087.22 1976 6424.584 1977 7029.639 1978 7928.054 1979 6596.933 1980 13956.602 1981 11529.048 1982 8808.134 1983 9673.546 1984 10469.285 1985 10403.279 1986 13465.224 1987 14458.981 1988 14304.967 1989 17366.912 1990 13982.271 1991 1437.464 1992 7455.011 1993 15196.048 1994 14594.66 1995 17825.287 1996 17869.291 1997 17806.952 1998 17993.969 1999 16468.497 2000 20703.882 2001 20256.508 2002 18166.318 2003 21169.591 2004 22783.071 2005 25547.989 2006 26255.72 2007 25558.99 2008 26640.755 2009 24121.526 2010 28155.226 2011 32885.656 2012 34759.493 2013 34594.478 2014 34308.452 2015 39097.554 2016 41627.784