Year	2011 PPP (%)
1981	62.5
1984	61.1
1987	59.6
1990	58.4
1993	57.2
1996	54.9
2002	53.6
2005	50.8
2008	48.4
2010	45.8
2011	42.7
2012	41.3
2013	39.7