It actully matters what nation your in. So prettymuch comes down to luck. 1st nation wins like 40k to split...2nd wins like 22k? 3rd like 15k and 4th like 10k. I'm pulling these numbers out of my ass but it's true.
It's definitely not a Constant ratio, it solely depends on the nation that you have got and then on your personal credit, like they said even if you have 20k points in a loosing nation(rank 4) the amount of ST would be low as compared to the same amount of credit in a winning nation. It's because the total number of ST 125K or so(don't remember the exact figures) are distributed among the nation's on the basis NATION POINTS at the end of Nw and then amongst players on the basis of their personal credit. So if there is a major difference between the NATIONS POINTS between the loosing and the winning nation(1st and 4th rank, assume it to be like a difference of 200points) then even with the same PERSONAL Credit you'll have different amount of ST given.