Year	Number of
1990	17450
1991	17800
1992	18140
1993	18480
1994	18800
1995	19100
1996	17950
1997	17720
1998	17710
1999	17630
2000	17980
2001	17920
2002	17810
2003	17760
2004	17420
2005	16890
2006	16780
2007	16910