Year	Number of
1990	18610
1991	18440
1992	18250
1993	18040
1994	17810
1995	17560
1996	18670
1997	17130
1998	16720
1999	16530
2000	19950
2001	18560
2002	16570
2003	16820
2004	16480
2005	14300
2006	15430
2007	15320