Year	2017 PPP (% of population)
1996	19.9
1997	40.7
1998	39.4
1999	47.1
2000	49.6
2001	52.4
2002	35.5
2003	35.9
2004	32.7
2005	35.2
2006	35.6
2007	37.8
2008	34.1
2009	34.3
2010	35.7
2011	33.3
2012	29.6
2013	25.3
2014	22
2015	20
2016	20.1
2017	20.1
2018	19.6
2019	18.5
2020	21.4
2021	19.1