Year Number 1961 264.17106422977844 1962 275.6026002872491 1963 283.75497771206807 1964 294.49450527247393 1965 303.13386407571033 1966 332.07055833031256 1967 340.02439064894196 1968 338.4248215593063 1969 339.24557260082037 1970 344.05967873491244 1971 353.5175672946673 1972 357.7388287746356 1973 366.18263412274626 1974 376.25039598678734 1975 392.51403879885873 1976 398.70032224731517 1977 406.1843781981952 1978 409.5929948531906 1979 411.8414983351966 1980 424.28936153683446 1981 424.5710925718313 1982 432.10071769273367 1983 437.23373616504654 1984 440.7450384888659 1985 448.8677531557381 1986 452.4894351260493 1987 462.469489408186 1988 461.17824475756146 1989 462.9426516315323 1990 457.1392388474595 1991 449.9187447720573 1992 412.5944584382872 1993 414.9112298855 1994 416.4907796583971 1995 418.76956707609014 1996 420.6288887022552 1997 421.7525110231411 1998 424.9373139430541 1999 427.7969182557781 2000 427.69677999234807 2001 421.6422817757495 2002 428.53141078219653 2003 386.15518586012973 2004 386.3253100766878 2005 386.91758154836697