Year	Number of
1980	11220
1981	10970
1982	11940
1983	11630
1984	10580
1985	10570
1986	10740
1987	11070
1988	10940
1989	10690
1990	11700
1991	11060
1992	11420
1993	12280
1994	11710
1995	11780
1996	12690
1997	13540
1998	14120
1999	14910
2000	15060
2001	14830
2002	14390
2003	15670
2004	14990
2005	15340
2006	16050
2007	16130