Year	2011 PPP (%)
1981	39.6
1984	33.6
1987	28.2
1990	29.7
1993	26.8
1996	21.5
1999	20.6
2002	16.6
2005	10.9
2008	8.4
2010	6.7
2011	5.4
2012	4.7
2013	2.8
2015	1.9