Year	2017 PPP (% of population)
1987	67.3
1990	65.1
1996	22.3
1998	29.8
2001	33.3
2004	20.2
2005	20.3
2007	14.9
2010	9.4
2011	9.6
2013	7.4
2015	5.1
2018	4.9