Year	2017 PPP (% of population)
1981	44.4
1986	28.6
1989	21.5
1990	20.8
1991	24.5
1992	21.2
1993	17.4
1994	14.7
1995	15.3
1996	17.6
1997	15.1
1998	11.9
1999	14
2000	14.8
2001	11.5
2002	10.5
2003	10.5
2004	9.8
2005	8.5
2006	8.2
2007	5.9
2008	5.7
2009	6.1
2010	4.1
2011	4.8
2012	4.4
2013	4.3
2014	4.3
2015	4.4
2016	4.1
2017	3.1
2018	4
2019	3.5
2020	6
2021	3.7
2022	3.3