Year	2011 PPP (% of population)
1981	42.1
1984	39.2
1987	35.3
1990	35.9
1993	34
1996	29.4
1999	28.6
2002	25.5
2005	20.7
2008	18.2
2010	15.7
2011	13.7
2012	12.8
2013	11.2
2015	10