Year	Number
2001	5.51525
2002	6.24795
2003	6.37635
2004	6.46782
2005	6.84661
2006	7.50259
2007	8.2608
2008	8.79561
2009	9.18954
2010	9.22332
2011	8.6038
2012	7.37891
2013	7.44905
2014	7.10141
2015	6.75418
2016	7.15698
2017	6.93556
2018	6.92216