Year	Number of
1990	15630
1991	14380
1992	13970
1993	13660
1994	13650
1995	14960
1996	17090
1997	21180
1998	24860
1999	20200
2000	21050
2001	22110
2002	22360
2003	23190
2004	23010
2005	22430
2006	22100
2007	21480