Year kt 1960 6552.929 1961 6857.29 1962 7521.017 1963 8958.481 1964 9068.491 1965 9787.223 1966 10498.621 1967 11151.347 1968 13164.53 1969 11653.726 1970 12420.129 1971 11441.04 1972 2427.554 1973 2933.6 1974 2819.923 1975 3347.971 1976 3630.33 1977 3575.325 1978 3751.341 1979 4209.716 1980 4807.437 1981 4851.441 1982 4704.761 1983 4253.72 1984 4400.4 1985 4840.44 1986 5295.148 1987 5331.818 1988 6006.546 1989 5771.858 1990 5342.819 1991 5269.479 1992 5379.489 1993 5482.165 1994 5896.536 1995 6728.945 1996 7168.985 1997 8415.765 1998 8258.084 1999 8859.472 2000 7693.366 2001 9875.231 2002 9889.899 2003 9875.231 2004 10630.633 2005 10608.631 2006 10931.327 2007 10179.592 2008 9915.568 2009 9999.909 2010 10850.653 2011 13410.219 2012 14891.687 2013 13971.27 2014 15797.436 2015 14701.003 2016 15449.071