Year	2017 PPP (%)
1981	43
1982	42.3
1983	41.2
1984	40.4
1985	39.6
1986	38.9
1987	38.6
1988	37.8
1989	37.6
1990	37.3
1991	36.4
1992	35.3
1993	34.9
1994	34
1995	33.6
1996	32.7
2002	31.4
2003	30.6
2004	29.6
2005	28.6
2006	27.6
2007	26.7
2008	26
2009	25.2
2010	22.9
2011	20.5
2012	19.3
2013	18.7
2014	18.1
2015	17.4
2016	16.9
2017	14.8
2018	12.5
2019	12
2020	13.5
2021	12.3
2022	10.9