1997 177 vehicles 1996 601 vehicles 1995 1,268 vehicles 1994 5,582 vehicles 1993 5,706 vehicles 1992 8,486 vehicles 1991 7,060 vehicles 1990 12,119 vehicles 1989 37,657 vehicles 1988 34,258 vehicles 1987 45,116 vehicles 1986 46,998 vehicles 1985 56,492 vehicles 1984 61,335 vehicles 1983 73,585 vehicles 1982 81,823 vehicles 1981 66,858 vehicles 1980 52,438 vehicles