Year	Number of
1990	10400
1991	11490
1992	12430
1993	13360
1994	14380
1995	15130
1996	15350
1997	16200
1998	17130
1999	17900
2000	18760
2001	18820
2002	19410
2003	19640
2004	19890
2005	19720
2006	19080
2007	18390