Year	2017 PPP (%)
1981	27.4
1982	27.9
1983	30.8
1984	30.5
1985	29.1
1986	24.1
1987	26.8
1988	27.2
1989	26.7
1990	28
1991	27.6
1992	27.6
1993	27.6
1994	26.2
1995	26
1996	27
1997	26.4
1998	26
1999	26.5
2000	24.9
2001	24.6
2002	24.1
2003	23.7
2004	22.5
2005	21.1
2006	18.7
2007	17.4
2008	16.3
2009	15.9
2010	14.7
2011	13.7
2012	13.1
2013	12.4
2014	12
2015	11.3
2016	11.4
2017	11.1
2018	10.9
2019	10.7
2020	10.5
2021	11.1
2022	9.5