Year % of population 2001 20.7 2002 19 2003 17.3 2004 15.6 2005 13.9 2006 12.9 2007 12.4 2008 12.3 2009 12 2010 11.8 2011 12.5 2012 15.2 2013 20 2014 27.2 2015 31.9 2016 34 2017 31.6 2018 33 2019 38.1 2020 43.7 2021 46