Year	2017 PPP (%)
1989	41.1
1990	41.4
1991	41
1992	40.2
1993	40.4
1994	39.8
1995	39.5
1996	38.6
1997	38
1998	38
1999	38
2000	37.8
2001	37.2
2002	36.6
2003	35.4
2004	33.1
2005	31.7
2006	30.5
2007	29
2008	27.7
2009	27.1
2010	26.1
2011	25.3
2012	24.6
2013	24
2014	23.4
2015	23.4
2016	23.2
2017	22.7
2018	22.3
2019	22.1