Year	2011 PPP (%)
1981	41.1
1984	42.2
1987	41.7
1990	42.3
1993	45.6
1996	44
1999	41.2
2002	38.9
2005	35.5
2008	31.8
2010	29.7
2011	29.2
2012	28
2013	27.2
2015	27.1