1993 925 vehicles 1992 1,511 vehicles 1991 6,888 vehicles 1990 13,924 vehicles 1989 19,424 vehicles 1989 5,961 vehicles 1988 21,334 vehicles 1988 20,459 vehicles 1987 24,534 vehicles 1987 24,473 vehicles 1986 27,666 vehicles 1986 25,887 vehicles 1985 29,260 vehicles 1985 21,734 vehicles 1984 34,550 vehicles 1984 24,092 vehicles 1983 20,565 vehicles 1983 5,277 vehicles 1982 17,800 vehicles 1981 18,091 vehicles 1980 312 vehicles