Year	2017 PPP (% of population)
1980	37.1
1988	29.5
1989	29.5
1991	27.3
1992	23.9
1996	34.2
1999	38.2
2000	33.2
2001	39.5
2002	30.9
2003	29.3
2004	28.8
2005	25.6
2008	24.1
2009	22.2
2010	20
2011	17.9
2012	16.8
2013	15.3
2014	14.3
2015	13
2016	12.9
2017	12.1
2018	12.2
2019	13.7
2020	19.3
2021	16.4
2022	14