Year	Number of
1990	4738
1991	5082
1992	5098
1993	5064
1994	5085
1995	5353
1996	5894
1997	6885
1998	8215
1999	9760
2000	11400
2001	12920
2002	14240
2003	15170
2004	15640
2005	15830
2006	15880
2007	15930