Year Number 1961 172509 1962 180420 1963 184644 1964 190476 1965 198135 1966 205905 1967 214594 1968 218497 1969 227906 1970 237250 1971 237010 1972 235196 1973 235610 1974 239009 1975 241287 1976 248924 1977 250736 1978 249874 1979 251051 1980 251638 1981 254958 1982 254040 1983 253686 1984 254615 1985 254614 1986 254979 1987 246510 1988 238500 1989 235505 1990 233231 1991 230322 1992 221514 1993 213078 1994 218638 1995 224909 1996 208847