If I was going to rent for any drive longer than 150 miles, I wouldn't own a car in the first place. Renting is a big hassle and multiplied by N trips sounds unpleasant. My trips are shorter and probably more frequent than your 620 mile multi-day affairs, though.
FYI, the information for the US can probably be derived from the raw data available here: https://nhts.ornl.gov/ . The high level web summary buckets all trips of 31+ miles into a single bucket, which isn't helpful for your question, but if you want to do the analysis on the data, it's available. Cheers.