Year	2011 PPP (%)
1981	58
1984	57.4
1987	56.5
1990	54.8
1993	54.6
1996	52.5
1999	51.9
2002	50
2005	47.3
2008	44.8
2010	41.7
2011	39.3
2012	38
2013	36.6
2015	33.9