Year	2017 PPP (%)
1984	39.7
1985	38.4
1986	37.2
1987	36.4
1988	34.9
1989	36.7
1990	36.3
1991	35.8
1992	34.9
1993	34.2
1994	32.7
1995	31.5
1996	30.3
1997	30.1
1998	30.2
1999	29.4
2000	28.5
2001	27.7
2002	26.4
2003	25.1
2004	23.5
2005	21.9
2006	21.1
2007	19.9
2008	19.2
2009	18.3
2010	16.8
2011	15.2
2012	14.4
2013	13.1
2014	12.6
2015	12.1
2016	11.8
2017	11.1
2018	10.2
2019	10
2020	10.7
2021	10.4
2022	9.8