Looking at the ECDC website the UK Gov't seem to use a factor of about 40 cases per 100k for quarantine to kick-in. Certainly Spain & Belgium fall into that category (there are no figures for Andorra or non-European countries). Spain currently is 89 (Canary Islands 7.3 just to show the injustice of it all) & Belgium 55, Greece has nearly doubled to 10.6 in a week, whereas Italy is fairly stable at 6.9.
Portugal is gradually decreasing and may be a candidate for being put on the exemption list. A bit late for their summer season unfortunately.