Year	Number
1971	15045
1972	17397
1973	21064
1974	22092
1975	23289
1976	24895
1977	23743
1978	24449
1979	28300
1980	32606
1982	35357
1983	40119
1984	45035
1985	48599
1986	53250
1987	58431
1988	59966
1989	61241
1990	51002
1991	54115
1992	55029
1993	58659
1994	61510
1995	62080
1996	62917
1997	64661
1999	53612
2000	60582
2001	62592
2002	65218