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 18.335 1979 1056.096 1980 1686.82 1981 2570.567 1982 3795.345 1983 4066.703 1984 4312.392 1985 4459.072 1986 3113.283 1987 3083.947 1988 3725.672 1989 4202.382 1990 4290.39 1991 4396.733 1992 4349.062 1993 4939.449 1994 5023.79 1995 5346.486 1996 6072.552 1997 6347.577 1998 6417.25 1999 6864.624 2000 7869.382 2001 8206.746 2002 8426.766 2003 8364.427 2004 8349.759 2005 7946.389 2006 9013.486 2007 9706.549 2008 10315.271 2009 9754.22 2010 10744.31 2011 9453.526 2012 9211.504 2013 8800.8 2014 8525.775 2015 8595.448 2016 9713.883