Year	2011 PPP (% of population)
1997	15.7
1998	27.2
1999	38.5
2000	35.7
2001	27.2
2002	16.3
2003	7.5
2004	8.6
2005	13.9
2006	2.4
2007	1.1
2008	1.3
2009	1
2010	0.5
2011	0.3
2012	0.3
2013	0.1
2014	0
2015	0
2016	0.2
2017	0.1