Year	2017 PPP (% of population)
1997	39.1
1998	53.1
1999	66
2000	64.7
2001	55.1
2002	40.5
2003	27.7
2004	28.7
2005	35.7
2006	10.6
2007	6.5
2008	7.2
2009	6.6
2010	4.5
2011	3.1
2012	2.3
2013	1.6
2014	0.8
2015	0.9
2016	1.1
2017	0.7
2018	0.6
2019	0.4
2021	0.3