Year	% of population
2000	3.1
2001	2.8
2002	2.5
2003	2.5
2004	2.5
2005	2.5
2006	2.5
2007	2.7
2008	3
2009	3.1
2010	3.1
2011	2.9
2012	2.8
2013	2.7
2014	2.8
2015	3
2016	3.1
2017	3.2