Year	2011 PPP (%)
1981	59.5
1984	53.5
1987	51.1
1990	51
1993	50.1
1996	47
1999	46
2002	42.7
2005	38.1
2008	34.8
2010	32.1
2011	30.1
2012	28.8
2013	26.8
2015	24.8