Year kt 1960 4497.692319016887 1961 4235.124334987794 1962 3418.246162452835 1963 3408.5214223036087 1964 4468.518098569211 1965 3992.0058312571527 1966 4177.908063595109 1967 4838.35020479574 1968 4740.605756214009 1969 5918.426361623881 1970 6740.1582862129835 1971 6422.226291580295 1972 7981.3512436458295 1973 8372.593951667684 1974 9746.833963594449 1975 12128.523948677484 1976 9913.112114503734 1977 10108.733468514662 1978 9683.257023540897 1979 9737.052895893901 1980 10446.180304183512 1981 11858.883209147965 1982 13921.722745116816 1983 14596.774656159021 1984 16000.68696390622 1985 15350.093455438007 1986 17786.15035180771 1987 19131.362493377328 1988 18705.786288589847 1989 18647.070767935104 1990 18025.66484100575 1991 19219.547094318834 1992 17140.039071130064 1993 19415.26549650131 1994 20999.597250666848 1995 20116.21227258667 1996 23328.084828758627 1997 22238.256622105357 1998 25020.441277290967 1999 24607.197960631274 2000 27879.50840999466 2001 29542.091986323194 2002 31555.451866327978 2003 31276.752885324928 2004 31965.689370630145 2005 34336.01629909285 2006 35270.6574050314 2007 36942.412372869934 2008 34653.98698461834 2009 29567.119221657616 2010 32764.989907703613 2011 26986.028335429422 2012 25557.384447712604 2013 24541.03376249124 2014 29283.062920114407 2015 30903.52399721119 2016 29240.028770674424