Year	Number
1973	3.59259
1974	2.71006
1975	3.81022
1976	3.52555
1977	2.7362
1978	1.75581
1979	2.40476
1980	2.36571
1981	2.992
1982	2.96186
1983	3.98729
1984	3.08805
1986	2.07377
2010	5.35458
2012	3.75849
2015	8.92957
2016	9.15