1998 147 vehicles 1997 221 vehicles 1996 357 vehicles 1995 469 vehicles 1994 1,503 vehicles 1993 4,445 vehicles 1992 6,055 vehicles 1991 126 vehicles 1990 163 vehicles 1989 135 vehicles 1988 178 vehicles 1987 146 vehicles 1986 3,701 vehicles 1985 5,728 vehicles 1984 5,274 vehicles 1983 1,711 vehicles 1982 4,549 vehicles 1981 1,221 vehicles