Year	$ 2017 PPP (%)
1999	1.66
2001	1.68
2002	1.41
2004	1.35
2005	1.12
2006	1.13
2007	1.27
2009	0.82
2010	0.62
2011	0.55
2012	0.45
2013	0.54
2014	0.68
2015	0.39
2016	0.66
2017	0.53
2018	0.37