This is a standardised unit of measurement for the hotness of a female, based on Mila Kunis being a 1, anything hotter being above 1 and anything not as hot being below. Also known as a NKU.
It has been discussed at length and there is no mathematical comparison between the 0-10 scale and the Nominal Kunis Unit scale. Save yourself the time and don't bother, it's mathematical anomaly.