Year 2011 PPP (% of population) 2003 1.7 2004 1.5 2005 1.7 2006 1.5 2007 1.5 2008 1.7 2009 1.7 2010 2.5 2011 2.5 2012 3 2013 3 2014 2.7 2015 3.5