Year	Number of
1980	39770
1981	42640
1982	49870
1983	52960
1984	45680
1985	41800
1986	45600
1987	45360
1988	44280
1989	45190
1990	48670
1991	56050
1992	31400
1993	54000
1994	48280
1995	56440
1996	63470
1997	63420
1998	72260
1999	79340
2000	75560
2001	76300
2002	81960
2003	88160
2004	98340
2005	123100
2006	145200
2007	147300