Year	2011 PPP (%)
1984	50.5
1987	49.8
1990	41.6
1993	41.4
1996	34.8
1998	46.3
1999	32.1
2000	31.1
2001	29
2002	21.1
2003	20.7
2004	21.5
2005	19.8
2006	23.4
2007	19.9
2008	19.2
2009	17.4
2010	15.1
2011	13.7
2012	12.6
2013	11.3
2014	10.2
2015	9
2016	8.3
2017	7.1