Year	2017 PPP (% of population)
1970	4
1975	2.5
1979	1.2
1984	1.2
1990	0.5
1996	0.7
1997	0.5
1998	0.5
1999	0.5
2000	0.5
2001	0.2
2002	0.2
2003	0.4
2004	0.3
2005	0.3
2006	0.2
2007	0.1
2008	0.1
2009	0.4
2010	0.3
2011	0.2
2012	0.3
2013	0.2
2014	0.2
2015	0.3
2016	0.3
2017	0.1
2018	0.1
2019	0.4
2020	0.4
2021	0.5