Year	% of population
2001	3.5
2002	3.3
2003	2.9
2004	2.6
2005	2.5
2006	2.5
2007	2.5
2008	2.5
2009	2.5
2010	2.5
2011	2.5
2012	2.5
2013	2.5
2014	2.5
2015	2.5
2016	2.5
2017	2.5
2018	2.5
2019	2.5
2020	2.5
2021	2.5