Year	% of population
2000	2.1
2001	2.1
2002	2.2
2003	2.3
2004	2.4
2005	2.4
2006	2.6
2007	2.6
2008	2.8
2009	2.9
2010	3.1
2011	3.3
2012	3.4
2013	3.5
2014	3.7
2015	3.9
2016	4.2
2017	4.5
2018	4.6
2019	4.9
2020	5.2
2021	5.6
2022	6