Year	%
2000	18.663696988558666
2001	18.380213842366086
2002	18.19369687650971
2003	18.098871573958284
2004	18.003715415599935
2005	17.933422037464418
2006	17.860073413759086
2007	17.806813527384463
2008	17.721020742978347
2009	17.669762668364793
2010	17.58522960846516
2011	17.61268343266516
2012	17.645255421769534
2013	17.73885930960972
2014	17.833661627410116
2015	17.961616157510218
2016	18.101868695762573
2017	18.241007166242337
2018	18.373428124574122
2019	18.494173755812717