1998 1,587 vehicles 1997 3,297 vehicles 1996 6,790 vehicles 1995 10,220 vehicles 1994 479 vehicles 1993 1,327 vehicles 1992 26,744 vehicles 1991 26,350 vehicles 1990 13,395 vehicles 1989 11,318 vehicles 1988 14,071 vehicles 1987 2,937 vehicles