Year % of population 2000 0 2001 0.1 2002 0.1 2003 0.2 2004 0.2 2005 0.2 2006 0.3 2007 0.3 2008 0.3 2009 0.4 2010 0.4 2011 0.4 2012 0.5 2013 0.5 2014 0.5 2015 0.6 2016 0.6 2017 0.7 2018 0.7 2019 0.7 2020 0.8 2021 0.8 2022 1