Year	Number
1971	9751
1972	11206
1973	10038
1974	12216
1975	12841
1976	14364
1977	15618
1978	15968
1979	17446
1980	17957
1981	18261
1982	18705
1983	18367
1986	18048
1987	19094
1988	18111
1989	17059
1990	15342
1991	14336
1992	14091
1993	13042
1994	12386
1995	11948
1996	12022
1999	213
2001	17