Year	2017 PPP (% of population)
1990	11.6
1991	12.9
1992	15.4
1993	17.7
1994	21.3
1995	19.4
1996	20.6
1997	18.5
1998	19.2
1999	24.6
2000	21.4
2001	19.2
2002	17
2003	16.1
2004	13.4
2005	12.3
2006	9.9
2007	7.8
2008	5.9
2009	5.2
2010	4.8
2011	4.2
2012	3.8
2013	3.3
2014	3.5
2015	3.2
2016	2.7
2017	2.7
2018	2.1
2019	2
2020	2.1
2021	1.8
2022	1.7