Year % of population 2000 14.8 2001 15 2002 15.2 2003 15.1 2004 14.9 2005 14.7 2006 14.4 2007 13.9 2008 13.4 2009 12.9 2010 12.2 2011 11.6 2012 10.8 2013 10.3 2014 9.7 2015 9.1 2016 8.7 2017 8 2018 7.6 2019 7.25 2020 7.1 2021 6.6 2022 6.4