Year	Number
1961	2733
1962	3772
1963	4577
1964	5404
1965	6364
1966	7205
1967	7960
1968	8640
1969	9733
1970	10765
1971	11735
1972	12696
1973	13808
1974	14818
1975	15172
1976	16301
1977	17690
1978	18767
1979	19847
1980	21269
1981	22299
1982	23124
1983	23736
1984	24403
1985	25100
1986	25807
1987	26797
1988	27596
1989	28498
1990	29237
1991	30035
1992	30447
1993	31305
1994	32117
1995	33228
1996	32722
1997	34376
1998	35930