To sort the table from the most frequent issue to the least, add

messages_packages = dict(sorted(messages_packages.items(), key=lambda mp: -len(mp[1])))

after line 54 (messages_packages["other errors"] = …).

I added that after line 63 (messages_packages = dict(sorted(messages_packages.items(), key=lambda mp: -len(mp[1])))) and now get

  File "/srv/jenkins/bin/rebuilder_stats.py", line 70, in main
    messages_packages[message].append(row[0])
    ~~~~~~~~~~~~~~~~~^^^^^^^^^
KeyError: 'packages missing on metasnap (maybe temporary)'