Year % of population 2001 21.4 2002 22.8 2003 23 2004 21.6 2005 18.7 2006 15.6 2007 13.6 2008 11.4 2009 9.5 2010 8.4 2011 7.4 2012 6.4 2013 5.4 2014 5.1 2015 5.5 2016 6.1 2017 6.3 2018 5.9 2019 6.2 2020 6.5 2021 7