Year	Number
1971	39.66667
1972	37.9
1973	17.50769
1974	13.93258
1976	15.88235
1977	13.70455
1978	15.81731
1979	36.27397
1980	14.19863
1981	14.60839
1982	11.83784
1983	12.83444
1984	8.8963
1985	10.22388
1986	11.71429