Year	Number
1974	18.61111
1975	18.97561
1976	14.10377
1977	13.66667
1980	12.05
1981	10.02415
1999	9.07595
2000	9.29365
2001	9.77824
2002	10.1342
2004	11.30126
2005	10.26909
2006	9.17405
2008	8.85873
2011	8.94215
2012	5.27476
2018	10.9653