You're not wrong. The assumption was that UCB is broadly representative. Looking at the full system data: https://www.universityofcalifornia.edu/infocenter/fall-enrol...

Given my own knowledge of the UC system, berkeley seems the most international, which is why I thought simply citing berkeley would be enough. But, point taken. Let's look into the system data.

The total UC enrollment is 286271. Of this, there are 40219 Non-resident international students, which means there are 14% international students in the UC system as a whole. Thus, my using just berkeley actually shifted the data in my opponent's favor, since -- as I hypothesized -- Berkeley does indeed have more international students as a percentage of enrollment.

Thanks for the data.

Campus-wise, my anecdotal observation would be Irvine or Davis has most of international students by percentage, though.

According to the data gp linked, Irvine and Davis are 16% and 27% white. If you were assuming all non-whites at Irvine or Davis were not American, let this be a teachable moment.

Perhaps you're right. I haven't visited either in years! When I was there last, UC Irvine had the most ethnic Asian students, but they were mostly Americans. That may have changed.