2000 1,657 vehicles 1999 20,566 vehicles 1998 29,388 vehicles 1997 29,090 vehicles 1996 20,917 vehicles 1995 25,436 vehicles 1994 21,918 vehicles 1993 14,506 vehicles 1992 9,934 vehicles 1991 6,230 vehicles 1990 3,973 vehicles 1989 288 vehicles