Year	Number of
1990	31930
1991	28280
1992	25460
1993	22180
1994	21180
1995	19890
1996	19080
1997	17840
1998	16630
1999	14740
2000	15140
2001	15620
2002	17630
2003	17150
2004	17690
2005	18360
2006	18880
2007	19410