Year % of population 2001 6.3 2002 5.7 2003 5.6 2004 5.4 2005 5.5 2006 5.6 2007 6.3 2008 6.7 2009 6.4 2010 5.8 2011 5.4 2012 5.8 2013 6.3 2014 6.6 2015 6.8 2016 6.4 2017 6 2018 5.3 2019 4.8 2020 4.7 2021 4.9