Year % of population 2006 24.6 2007 23.6 2008 22.1 2009 21.6 2010 22.3 2011 22.9 2012 23 2013 25.1 2014 25.4 2015 25.3 2016 23.6 2017 23.5 2018 23.8 2019 23.4 2020 22.5 2021 21.2