Not 100% sure, but I believe to a first approximation that the index includes the XXXX largest (non-US) publicly traded stocks, at market weight. Some smaller stock exchanges might be excluded even if they include stocks that might otherwise qualify. Currency fluctuations will cause some ongoing difficulty in settling which stocks are "largest".
So you should expect country percentages to vary.
Note also that TotInt is in the process of moving to a new all-world-ex-US index; the new one is from FTSE.