Year	2011 PPP (%)
1981	39.3
1984	35.9
1987	32.8
1990	32.8
1993	31.4
1996	27.8
1999	26.9
2002	24.2
2005	20.2
2008	17.9
2010	16
2011	14.3
2012	13.5
2013	12.1
2015	10.9