Upvote:6
Total estimates for the number of people displaced by World War II are at least as high as 60 million. The question is how many of these displaced people crossed international borders. I'm not sure, but it could easily be in the millions. So the share may be small, but still significant.
Here are a couple of specific figures I am picking out of an excellent book on the history of global migrations. This is not a comprehensive list.
Page 476 of the book includes a detailed map of population movements within and out of Europe from 1939 to 1949.