1991 133 vehicles 1990 9,061 vehicles 1989 17,642 vehicles 1988 29,985 vehicles 1987 30,079 vehicles 1986 36,335 vehicles 1985 35,583 vehicles 1984 34,759 vehicles 1983 31,259 vehicles 1982 21,541 vehicles 1981 20,708 vehicles 1980 25,377 vehicles