Year % of population 1983 7.2 1987 6.7 1990 8.2 1993 10 1999 7.5 2004 10.1 2005 9.1 2006 9.1 2007 8.8 2008 9.8 2009 9.3 2010 9.6 2011 9.2 2012 8.8 2013 9.6 2014 9.3 2015 9.3 2016 9.5 2017 9 2018 9.2 2019 9.9 2020 9 2021 8.8