Year	% of population
1987	20
1994	16.5
1995	16.7
1996	15.7
2000	12.9
2002	12.7
2003	13.3
2004	13.5
2005	12.7
2006	11
2007	10
2008	11.5
2009	12.5
2010	12.6
2011	13.2
2012	13.6
2013	14.1
2014	11.9
2015	11.5
2016	10.9
2017	9.7
2018	8.5
2019	9.5
2020	7.8
2021	7.8