Year	Number
1994	14.03921
1996	14.21311
1997	13.07584
1998	15.04589
1999	13.35495
2000	13.46781
2001	13.38618
2003	11.8723
2004	11.17635
2005	14.14158
2006	14.29281
2007	14.50064
2008	14.20683
2009	13.77188
2010	14.18609
2011	13.93791
2012	13.92247
2014	13.31329
2015	13.00691
2016	12.92735
2017	12.44044