Year	2011 PPP (% of population)
1981	65.5
1986	54.7
1989	42.4
1990	39.9
1991	44.5
1992	41
1993	35
1994	30.2
1995	31.8
1996	34.9
1997	32.2
1998	27.2
1999	30
2000	30
2001	23.2
2002	22.3
2003	21.8
2004	22.6
2005	20.3
2006	20
2007	15.9
2008	15.5
2009	15.2
2010	12.9
2011	13.2
2012	12.3
2013	12.3
2014	11.9
2015	11.5
2016	10.7
2017	9.7