Year	2011 PPP (% of population)
1981	82.5
1984	82.7
1987	81.9
1990	82.2
1993	82.8
1996	81.4
1999	80.7
2002	77
2005	72.4
2008	67.7
2010	64.3
2011	62.1
2012	60.3
2013	57.8
2015	54.7