Year	Number of
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	13
1998	101
1999	630
2000	1981
2001	2929
2002	3250
2003	3780
2004	4249
2005	4549
2006	4958
2007	5444