Year	2017 PPP (% of population)
1971	3
1973	2
1975	2
1977	1.7
1979	1.5
1981	1
1982	1
1984	1
1985	1
1986	1.2
1987	0.7
1988	0.7
1989	1.2
1990	1.2
1991	1.2
1992	1
1993	1.2
1994	1
1995	1
1996	0.5
1997	0.5
1998	0.7
1999	0.5
2000	0.5
2001	0.5
2002	0.5
2003	0.5
2004	0.2
2005	0.5
2006	0.5
2007	0.2
2008	0.2
2009	0.2
2010	0.2
2011	0.5
2012	0.5
2013	0.5
2014	0.5
2015	0.5
2016	0.5
2017	0.5
2018	0.5
2019	0.5