Year	% of population
2004	20.5
2005	20
2006	19.1
2007	20.9
2008	20.3
2009	20.5
2010	19.2
2011	18.6
2012	20.6
2013	19.1
2014	22.2
2015	21.9
2016	22.9
2017	22.9
2018	20.6
2019	20.9
2020	20
2021	20.9