Year	% of population
2001	3.8
2002	3.7
2003	3.6
2004	3.4
2005	3.4
2006	3.5
2007	3.6
2008	3.6
2009	4.1
2010	4.7
2011	5.1
2012	5.2
2013	5.5
2014	6.3
2015	6.5
2016	6.2
2017	5.7
2018	5.7
2019	6.1
2020	6.9
2021	7.9