Year	Total
1971	7526
1972	7700
1973	8070
1974	8353
1975	8599
1976	8902
1977	9099
1978	9406
1979	11280
1980	12220
1981	12900
1982	14080
1983	15380
1984	16000
1985	16460
1986	16420
1987	15950
1988	16510
1989	16960
1990	17230
1991	16820
1992	16850
1993	16450
1994	16480
1995	15820
1996	15820
1997	16090
1998	17250
1999	18660
2000	19550
2001	18370
2002	20110
2003	20600
2004	20890
2005	21400
2006	21400
2007	22150
2008	22980
2009	23470