Year	2017 PPP (% of population)
1979	18.2
1989	31.8
1991	28.8
1995	22.7
1997	21.8
1998	21.6
1999	19.3
2000	18.3
2001	22.8
2002	19.5
2003	18.7
2004	17.6
2005	16.4
2006	17.4
2007	14.9
2008	10.5
2009	8
2010	9.1
2011	7.3
2012	8.7
2013	7
2014	7.4
2015	5.6
2016	5.8
2017	5.3
2018	4.4
2019	3.7
2021	4.3
2023	4.4