Year	%
2000	20.59081077516697
2001	20.645601844691107
2002	20.5409681044027
2003	20.34489135637203
2004	20.0435694751104
2005	19.821539070045596
2006	19.620749998729266
2007	19.357483305884596
2008	19.225239401513026
2009	19.094151213994163
2010	18.88647427238115
2011	18.48439237689717
2012	18.581477188417455
2013	18.16422677776264
2014	18.115485107487526
2015	18.279392538782336
2016	17.928160645169516
2017	17.55001377901744
2018	17.536706035049054
2019	17.42317261471639