Year	%
2006	16.3
2007	16.6
2008	16.7
2009	16.9
2010	17.1
2011	17.1
2012	17.1
2013	17.4
2014	17.8
2015	17.7
2016	17.9
2017	17.4
2018	17.3
2019	17.7
2020	17.8
2021	17.7