Year	Number of
1990	955
1991	1393
1992	1943
1993	2685
1994	3615
1995	4757
1996	6021
1997	7563
1998	9320
1999	11300
2000	13530
2001	15830
2002	18060
2003	19920
2004	21070
2005	21640
2006	21800
2007	21840