Basically i have a set of data and i need too find the equation of the curve, or some other way of estimating the missing values, the data set is as follows.

Spoiler:

so far, all iv managed too do with it is calculate spearmans rank, which is

-0.96929 ideally, id like too come up with an equation with a method of working it out, and then go on too predict the missing values, can someone help me out?

thanks in advance.