Year % of population 2002 1.3 2003 2.6 2004 3.9 2005 5.2 2006 14.5 2007 7.9 2008 9.3 2009 4.7 2010 6 2011 13.5 2012 14.9 2013 16.3 2014 17.2 2015 20.1 2016 22.9 2017 26 2018 28.4 2019 30.9 2020 33.4 2021 35.8 2022 37.4