Year	2017 PPP (% of population)
1977	97.8
1983	97.4
1987	96.7
1993	96.7
2004	94.8
2009	93.4
2011	90.3
2015	88.9
2016	88.7
2017	85.4
2018	82.7
2019	80.7
2020	83
2021	81.8