Year	2017 PPP (% of population)
1977	89.1
1983	86.6
1987	84.2
1993	82.6
2004	77.5
2009	72.6
2011	63.1
2015	61
2016	59.9
2017	54.5
2018	47
2019	44
2020	48.3
2021	44.1