Year Years 1800 486.4 1900 485.3 1930 455 1956 324.5 1957 318.7 1958 313 1959 307.3 1960 301.9 1961 296.7 1962 291.5 1963 286.5 1964 281.2 1965 276.2 1966 271.2 1967 266 1968 260.4 1969 254.9 1970 249.3 1971 243.7 1972 237.9 1973 231.9 1974 225.9 1975 220 1976 214 1977 208.2 1978 202.5 1979 197 1980 191.6 1981 186.4 1982 181.1 1983 176 1984 171.2 1985 166.4 1986 161.8 1987 157.3 1988 153 1989 148.8 1990 144.6 1991 140.5 1992 136.4 1993 132.3 1994 128.1 1995 123.9 1996 119.8 1997 115.8 1998 111.8 1999 108.1 2000 104.4 2001 101 2002 97.8 2003 94.9 2004 92.2 2005 89.7 2006 87.4 2007 85.2 2008 83.1 2009 81 2010 174.4 2011 77 2012 75 2013 72.8