Year	2011 PPP (% of population)
1981	85.5
1984	84.3
1987	82.9
1990	81.7
1993	80.4
1996	77.2
2002	75.5
2005	71.5
2008	67.9
2010	63.9
2011	58.9
2012	56.6
2013	53.9