Year	Number
1971	19.91364
1972	9.92688
1973	11.368
1974	16.70652
1982	15.55814
2008	16.38978
2010	14.2236
2011	6.06687
2013	11.3074
2014	9.05427
2015	10.28717
2016	11.53832
2017	11.67438