Year	Number
1972	5.26471
1973	6.1
1974	9.63333
1975	8.375
1976	8.5
1977	8.88571
1978	8.96471
1979	9.55556
1980	7.7
1981	7.89583
1982	10.05344
1983	10.47445
1984	11.83916
1985	10.2
1986	10.76018
1987	9.93091
1991	8.94
1996	11.56863
2012	21.7716
2016	20.10643
2017	18.25175