Year kt 1960 0 1961 0 1962 0 1963 0 1964 0 1965 0 1966 0 1967 0 1968 0 1969 0 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 0 1991 0 1992 0 1993 0 1994 0 1995 0 1996 0 1997 198.018 1998 1595.145 1999 4455.405 2000 4657.09 2001 5163.136 2002 6252.235 2003 6039.549 2004 7565.021 2005 8591.781 2006 8335.091 2007 8723.793 2008 9479.195 2009 9658.878 2010 10278.601 2011 10223.596 2012 9006.152 2013 8602.782 2014 7953.723 2015 9332.515 2016 9845.895