Year	% of population
2006	22.4
2007	18.6
2008	17.3
2009	18.1
2010	19.5
2011	18.8
2012	19.3
2013	19.5
2014	18.8
2015	20
2016	19.2
2017	18.4
2018	17.2
2019	17.6
2020	15.5
2021	15.8