Year	2011 PPP (% of population)
1981	46.7
1984	51.3
1987	47
1990	49.3
1993	49.1
1996	48.1
1999	47
2002	45
2005	40.9
2008	33.2
2010	31.1
2011	29.6
2012	27.7
2013	27.2
2015	26.3