Year	%
2004	22.6
2005	21.5
2006	22.1
2007	22.3
2008	22.4
2009	22.7
2010	22.7
2011	23
2012	23.2
2013	22.9
2014	23.5
2015	23.2
2016	23.2
2017	23.5
2018	23.5
2019	23.2
2020	23.6
2021	23.4