Year	2017 PPP (% of population)
1980	60.6
1988	54.1
1989	55.4
1991	52.1
1992	54.2
1996	61.5
1999	64.3
2000	59.5
2001	67
2002	57.7
2003	58
2004	57.3
2005	53.5
2008	48.5
2009	47.3
2010	44.6
2011	41.6
2012	39.8
2013	37.6
2014	35.4
2015	34.6
2016	34.3
2017	33.7
2018	33.9
2019	34.8
2020	42.2
2021	38.8
2022	34.8