Year	2017 PPP (% of population)
1981	71.1
1986	63.4
1989	47.4
1990	45.6
1991	51.4
1992	48
1993	40.9
1994	36.6
1995	37.1
1996	41.3
1997	38.1
1998	33.6
1999	36.1
2000	36.1
2001	28
2002	27.8
2003	26.5
2004	27.9
2005	25.4
2006	25.1
2007	20.3
2008	20
2009	19.4
2010	15.6
2011	16.4
2012	15.6
2013	15.6
2014	15.1
2015	14.8
2016	14.2
2017	12.9
2018	13.9
2019	13.7
2020	19.9
2021	14.5
2022	14.1