Year	Number
1971	24148
1972	24822
1973	25510
1974	26667
1975	27780
1976	28533
1977	28883
1978	29528
1979	29581
1980	29482
1981	29245
1982	29012
1983	29384
1984	27944
1985	27401
1988	27259
1989	27467
1990	27854
1991	28270
1992	28195
1993	29132
1994	29600
1995	30037
1996	29415