Year	2011 PPP (% of population)
1981	13.5
1984	16.5
1987	13.5
1990	14.8
1993	14
1996	13.7
1999	13.5
2002	11.8
2005	9.9
2008	6.9
2010	6.2
2011	5.7
2012	4.7
2013	4.6
2015	3.9