Year	2017 PPP (% of population)
1981	22.7
1988	18
1990	12.3
1992	9
1994	4.5
1996	3.1
1998	2.2
1999	4
2000	4
2002	1.8
2004	1.2
2006	0.9
2007	0.5
2008	0.3
2009	0.2
2010	0.3
2011	0.1
2012	0.1
2013	0.1
2014	0.1
2015	0
2016	0
2017	0
2018	0
2019	0.1
2020	0
2021	0