Exchange rates are better almost across the board than The Force Awakens. EUR, AUD, JPY, RUB are all up from December 2015 against the dollar. The only notable exception is the pound, which is down slightly, but overall, given the share of the overseas gross that these markets make up collectively compared to the share the UK makes up, exchange rates are definitely more favorable for The Last Jedi. There's even the service fees in China which boost Chinese grosses by about 6%, which TFA didn't have.
So yeah, the overseas drop is worse overall than the domestic drop, the reason being that The Force Awakens over-performed to a significant degree in markets like Russia, South Korea, China, Mexico, Brazil, etc. etc. That's the only reason why TFA sniffed a 45%/55% split - The Last Jedi is simply reverting to the Star Wars norm. In the case of episodic movies, you're probably looking at 47-49%/51-53% splits, and it wouldn't be surprising for the spinoffs to regularly have splits that are over 50% domestic.