1999 1,576 vehicles 1998 2,214 vehicles 1997 3,268 vehicles 1996 3,195 vehicles 1995 2,551 vehicles 1994 2,112 vehicles 1993 2,074 vehicles 1992 1,419 vehicles 1991 771 vehicles 1990 1,175 vehicles 1989 1,966 vehicles 1988 1,476 vehicles