Year	2011 PPP (%)
1981	27.5
1984	27.9
1987	27.5
1990	28.5
1993	31.1
1996	29.6
1999	27.5
2002	24.8
2005	21.5
2008	18.3
2010	16.8
2011	16.2
2012	15.2
2013	14.5
2015	14.1