Non-linear regression line fit
I tried to estimate a few of your data values from the scatter plot you provided.

Then I performed a power model regression and came up with

$y = (5.777 \cdot 10^{-16}) \cdot 1.404^{x}.$



The estimated values I used are below.

$(70, 0.01), (75, 0.012), (80, 0.015), (90, 0.025), (95, 0.075), (98, 0.15), (99, 0.20), (99.5, 0.25), (99.9, 0.32)$

Of course, your actual model will differ because you have the actual data set. I just eyeballed a few points so I could test the power fit.