Year	Number of
1990	28980
1991	28430
1992	27860
1993	27270
1994	26650
1995	26010
1996	25600
1997	24950
1998	24730
1999	24270
2000	23820
2001	23120
2002	21480
2003	20670
2004	20020
2005	20280
2006	19500
2007	18640