Year % of population 2001 24.5 2002 23.2 2003 21.7 2004 19.8 2005 18.1 2006 16.5 2007 13.6 2008 11.8 2009 10.7 2010 10.8 2011 10.7 2012 11 2013 10.8 2014 10.6 2015 9.5 2016 8.3 2017 7.3 2018 6.7 2019 6.3 2020 5.9 2021 5.7