Year	2017 PPP (%)
1990	61.8
1991	62.6
1992	63.1
1993	63.9
1994	64.1
1995	63.8
1996	63.4
1997	63.2
1998	63.2
1999	63.2
2000	63.2
2001	62.7
2002	62.4
2003	61.9
2004	60.5
2005	59.5
2006	58.5
2007	57.7
2008	56.8
2009	56.5
2010	55.4
2011	54.8
2012	54.1
2013	53.6
2014	53
2015	53
2016	52.9
2017	52.6
2018	52.2
2019	52.1