Year	% of population
2002	19.1
2003	19.2
2004	18.5
2005	20.4
2006	19
2009	27
2010	26.8
2011	26.2
2012	24.2
2013	22.1
2014	21.5
2015	21.9
2016	22.2
2017	21.9
2018	21.6
2019	21.8