Year % of population 2001 12.4 2002 11.3 2003 11 2004 10 2005 9.4 2006 9.3 2007 9.2 2008 9 2009 6.9 2010 5.6 2011 5 2012 5.8 2013 6 2014 6 2015 6.3 2016 6.3 2017 5.8 2018 4.5 2019 3.1 2020 2.7 2021 2.8