Year	%
2006	23
2007	23.1
2008	23.1
2009	22.7
2010	23
2011	22.6
2012	22.5
2013	22.5
2014	22.5
2015	22.5
2016	22.6
2017	22.5
2018	22.6
2019	22.5
2020	22.3