Year	Number
1971	417
1972	469
1973	467
1974	558
1975	567
1976	569
1977	661
1978	682
1979	734
1980	786
1981	831
1982	870
1983	986
1984	1051
1985	1166
1986	1208
1987	1240
1988	1296
1989	1290
1990	1335
1991	1497
1992	1525
1993	1592