Year	Number of
1990	19000
1991	19760
1992	20330
1993	20810
1994	21370
1995	22130
1996	21890
1997	23820
1998	25780
1999	27870
2000	30500
2001	32740
2002	36590
2003	40480
2004	44740
2005	48400
2006	51800
2007	55170