Year	Number
1961	22630
1962	24530
1963	28500
1964	33500
1965	39318
1966	44774
1967	50857
1968	52300
1969	57000
1970	61945
1971	67536
1972	70540
1973	77802
1974	84043
1975	93424
1976	102656
1977	112650
1978	122268
1979	132000
1980	140305
1981	152254
1982	159516
1983	168715
1984	178857
1985	183410
1986	193257
1987	203161
1988	207567
1989	211651
1990	215755
1991	223718
1992	228051
1993	231177
1994	234844
1995	236197
1996	240125
1997	242446
1998	242678
1999	249819
2000	253785
2001	254527
2002	256858
2003	257737
2004	258476
2005	259766
2006	259613