Year	2011 PPP (% of population)
1980	1.2
1986	0
1987	0.9
1991	4.4
1992	4.9
1993	5.8
1994	5.5
1995	8.6
1996	9.5
1997	8.8
1998	10.1
1999	10.7
2000	12.6
2001	17.3
2002	26.2
2003	15.1
2004	11.7
2005	9.5
2006	7.9
2007	6.7
2008	6.3
2009	5.7
2010	5.3
2011	2.4
2012	2.7
2013	2.3
2014	2.6
2016	2.4
2017	2.4