Year	2011 PPP (%)
1992	20
1996	27.3
1999	30.5
2000	27.3
2001	31
2002	24.9
2003	22.7
2004	22.2
2005	19.8
2008	19
2009	17.7
2010	16
2011	14.2
2012	13.7
2013	12.7
2014	11.7
2015	11
2016	10.9
2017	10.2