Year	Number
1961	12837
1962	13200
1963	13500
1964	14000
1965	14500
1966	15000
1967	15400
1968	15572
1969	16962
1970	17300
1971	17566
1972	18500
1973	20036
1974	20889
1975	21500
1976	22000
1977	22468
1978	28300
1979	34189
1980	36000
1981	38639
1982	41900
1983	45200
1984	48500
1985	51856
1986	52000
1987	52290
1988	53000
1989	55000
1990	57000
1991	59000
1992	61000
1993	78099
1994	78846
1995	89080
1996	88000
1997	86000
1998	86000
1999	86000
2000	86255
2001	92203
2002	93340
2003	94482
2004	96265
2005	98051
2006	100317
2007	102584
2008	103188