Year kt 1960 4374.731 1961 4316.059 1962 4140.043 1963 4129.042 1964 3784.344 1965 4180.38 1966 5977.21 1967 6098.221 1968 6538.261 1969 7876.716 1970 6842.622 1971 7623.693 1972 7264.327 1973 9383.853 1974 9614.874 1975 11301.694 1976 11045.004 1977 13879.595 1978 13175.531 1979 15372.064 1980 18635.694 1981 18169.985 1982 18657.696 1983 22038.67 1984 22786.738 1985 22522.714 1986 22779.404 1987 25111.616 1988 27308.149 1989 25173.955 1990 23223.111 1991 26087.038 1992 28701.609 1993 28015.88 1994 30476.437 1995 27102.797 1996 27429.16 1997 30043.731 1998 33116.677 1999 22207.352 2000 30890.808 2001 28481.589 2002 29519.35 2003 31968.906 2004 32845.319 2005 31077.825 2006 35261.872 2007 38353.153 2008 37392.399 2009 44928.084 2010 45401.127 2011 46959.602 2012 48580.416 2013 51961.39 2014 52900.142 2015 55562.384 2016 53519.865