Year Total 1960 1.72 1961 4.902 1962 3.87 1963 0.172 1964 6.45 1965 8.514 1966 7.74 1967 8.342 1968 8.428 1969 7.31 1970 8.256 1971 4.73 1972 5.59 1973 4.042 1974 7.138 1975 6.106 1976 3.956 1977 24.26 1978 24.2 1979 26.12 1980 29.42 1981 30.28 1982 28.66 1983 28.4 1984 30.91 1985 30.67 1986 26.1 1987 33.74 1988 36.56 1989 35.15 1990 28.8 1991 30.51 1992 45.59 1993 44.19 1994 45.32 1995 44.56 1996 37.38 1997 42.5 1998 53.08 1999 53.44 2000 57.28 2001 58.21 2002 56.07 2003 58.12 2004 66.66 2005 88.32 2006 91.87 2007 94.62 2008 101.3 2009 106.1 2010 104