Year % of population 2001 9.6 2002 9.1 2003 8.3 2004 7.6 2005 5.4 2006 3.1 2007 2.5 2008 2.5 2009 2.5 2010 2.5 2011 2.5 2012 2.5 2013 2.5 2014 2.5 2015 2.5 2016 2.5 2017 2.5 2018 2.5 2019 2.5 2020 2.5 2021 2.5