Year	%
2006	26.6
2007	27.9
2008	25.7
2009	25.7
2010	26.9
2011	26
2012	27.4
2013	27.6
2014	28.8
2015	28.7
2016	31.4
2017	31.9
2018	32.6
2019	31.4
2020	32.6
2021	29.9