Year	2017 PPP (%)
1989	22.2
1990	22.5
1991	22.2
1992	21.6
1993	21.7
1994	21.4
1995	21.2
1996	20.4
1997	19.9
1998	19.8
1999	19.6
2000	19.4
2001	18.7
2002	18.1
2003	17.2
2004	15.6
2005	14.6
2006	13.7
2007	12.7
2008	11.9
2009	11.6
2010	10.8
2011	10.4
2012	9.9
2013	9.6
2014	9.4
2015	9.5
2016	9.6
2017	9.5
2018	9.3
2019	9.3