Year	2017 PPP (% of population)
1997	35.9
1998	34.9
1999	36.3
2000	35.4
2001	37.5
2002	34.2
2003	32.3
2004	32.8
2005	35.2
2006	30.4
2007	26.5
2008	22.7
2009	20.5
2010	17.8
2011	16.3
2012	14.8
2013	14
2014	13.1
2015	12.8
2016	12.4
2017	12.4
2018	10.7
2019	9.6
2020	17.4
2021	10
2022	9.5