Year	%
2003	22
2004	22.4
2005	22.3
2006	21.9
2007	23
2008	22.6
2009	22.5
2010	22.8
2011	22.8
2012	22.6
2013	22.6
2014	22.5
2015	23.2
2016	23.6
2017	23.7
2018	23.7
2019	23.2
2020	23.1
2021	23.1