Year	2011 PPP (% of population)
1987	32.4
1994	34.7
1998	35.7
1999	40.2
2000	49.9
2003	30.1
2004	31.9
2005	25.7
2006	19.8
2007	19.2
2008	18.1
2009	17.2
2010	14.7
2011	12.2
2012	11.4
2013	10.1
2014	8.6
2015	9.4
2016	9.4
2017	8.7