Year	2011 PPP (% of population)
1981	24.7
1986	13.2
1989	12
1990	9.9
1991	11.7
1992	9.6
1993	8
1994	6.6
1995	6.9
1996	8
1997	6.5
1998	5.1
1999	6.4
2000	6.5
2001	4.7
2002	4.5
2003	4.4
2004	4.3
2005	3.1
2006	3.2
2007	1.7
2008	2.2
2009	2.4
2010	1.5
2011	1.6
2012	1.6
2013	1.6
2014	1.4
2015	1.5
2016	1.3
2017	1