Year	Number
1994	18.33845
1999	15.66547
2000	14.32289
2001	14.10571
2006	10.58928
2007	12.82706
2008	12.15258
2009	11.89762
2010	11.72345
2011	11.7829
2012	11.54548
2013	11.49954
2016	11.26704
2017	11.31153