Year	Total
1971	18170
1972	18650
1973	19050
1974	19710
1975	20460
1976	21690
1977	22990
1978	24120
1979	25620
1980	27210
1981	28120
1982	29540
1983	29720
1984	30500
1985	31810
1986	31540
1987	31000
1988	30590
1989	30370
1990	28910
1991	28080
1992	24450
1993	22500
1994	21280
1995	20030
1996	17870
1997	17380
1998	15850
1999	17670
2000	18790
2001	19280
2002	18650
2003	19260
2004	20240
2005	22030
2006	22250
2007	19680
2008	20810
2009	20260