Year	2017 PPP (%)
1984	73.4
1987	73.2
1990	67.7
1993	67.4
1996	62.1
1998	70.6
1999	61.3
2000	60.9
2001	59.1
2002	51.5
2003	50.5
2004	50.9
2005	49.3
2006	52.3
2007	47.9
2008	47.4
2009	45.7
2010	41.4
2011	39.1
2012	38.1
2013	36.1
2014	34.3
2015	32.2
2016	29.8
2017	27.4
2018	25.5
2019	24.5
2020	23.7
2021	23.1
2022	22.2
2023	20.8