Year	2011 PPP (% of population)
1984	91.7
1987	92.7
1990	87
1993	86.6
1996	79.7
1998	90.2
1999	80.1
2000	79.9
2001	77.6
2002	65
2003	62.7
2004	62.9
2005	61.3
2006	65.7
2007	58.4
2008	57.3
2009	54.7
2010	48.1
2011	45.1
2012	43.3
2013	40.8
2014	37.9
2015	33.1
2016	31
2017	27.3