Year	% of population
2001	67.8
2002	63.5
2003	59.1
2004	55.4
2005	52.6
2006	49.8
2007	46.7
2008	43.6
2009	32.6
2010	22.6
2011	14.2
2012	13.3
2013	12.7
2014	12.5
2015	13.5
2016	14.4
2017	14.7
2018	15.2
2019	17.5
2020	20.1
2021	21.6