Year	% of population
2001	6.1
2002	6.1
2003	6
2004	5.8
2005	5.5
2006	5.6
2007	5.4
2008	4.9
2009	4.7
2010	5.1
2011	5.9
2012	5.7
2013	5.4
2014	5.6
2015	5.5
2016	5.2
2017	4
2018	3.3
2019	2.7
2020	2.5
2021	2.8