Year Total 1971 141600 1972 145900 1973 149000 1974 156500 1975 165700 1976 169800 1977 174100 1978 177500 1979 180800 1980 186900 1981 200000 1982 210700 1983 221500 1984 233200 1985 239400 1986 251200 1987 259200 1988 273000 1989 281500 1990 291800 1991 301600 1992 306200 1993 309900 1994 321100 1995 335800 1996 342300 1997 353100 1998 351900 1999 359400 2000 366400 2001 374500 2002 383600 2003 396400 2004 409500 2005 422400 2006 437900 2007 452700 2008 468300 2009 502500