Year	$ 2017 PPP (%)
1999	26.43
2001	40.24
2002	32.08
2004	31.91
2005	29.14
2006	24.84
2007	22.26
2009	11.58
2010	9.12
2011	7.25
2012	6.42
2013	8.07
2014	8.18
2015	5.57
2016	8.79
2017	8.23
2018	3.68