Year	% of population
2001	34.1
2002	35.6
2003	36.9
2004	35.4
2005	33.7
2006	31.4
2007	30.9
2008	30.7
2009	29.9
2010	28.3
2011	27.2
2012	29.3
2013	33
2014	37.7
2015	40.4
2016	41.9
2017	42.8
2018	44.7
2019	47.1
2020	49.5
2021	51