Year	2011 PPP (% of population)
1981	19.6
1988	14.3
1990	9.4
1992	6.6
1994	3.2
1996	2.2
1998	1.5
1999	2.5
2000	2.5
2002	1.1
2004	0.8
2006	0.7
2007	0.3
2008	0.1
2009	0.2
2010	0.1
2011	0
2012	0.1
2013	0
2014	0
2015	0
2016	0
2017	0