I have some decile distributions of income (1th to 9th decile). Now I would like to know the income of the 99th percentile. My idea is to use the nine data points that I have, to build a (probably not linear) regression model (income ~ percentile) with which I can estimate the income of the 99th percentile.
As I am not that familiar with using deciles, I wanted to know if my approach makes sense, and (if not) what else could be done.
Thank you in advance and kind regards :)