Year	%
2003	30.2
2004	30.9
2005	30.6
2006	29.7
2007	28.9
2008	28.9
2009	27.5
2010	28.3
2011	28.7
2012	27.8
2013	27.5
2014	27.4
2015	27.3
2016	27.6
2017	26.7
2018	26.6
2019	26
2020	26.9
2021	27.6