Year	Number
1970	6580
1971	6692
1972	7951
1973	8456
1974	8822
1975	11629
1976	11549
1977	10119
1978	8560
1979	8799
1981	9633
1982	8882
1984	8607
1986	8252
1987	9639
1988	10536
1989	9331
1990	9846
1991	10257
1992	11370
1993	12259
1994	12860
1995	9941
1998	15663
2012	29327
2016	43678