Year	Number
1961	51952
1962	57500
1963	65351
1964	75386
1965	81356
1966	90810
1967	92826
1968	96368
1969	101906
1970	107290
1971	114184
1972	115606
1973	116513
1974	116816
1975	119533
1976	128024
1977	138549
1978	138840
1979	139750
1980	146592
1981	155993
1982	169000
1983	167691
1984	174005
1985	184408
1986	185208
1987	183850
1988	165100
1989	151700
1990	132882
1991	132761
1992	146790
1993	158126
1994	161223
1995	163370
1996	165281
1997	163016
1998	164756
1999	163883
2000	160053
2001	164221
2002	169240
2003	169177
2004	171811
2005	173043
2006	174563
2007	174003
2008	174790
2009	176841