Do the Ubuntu repositories just keep growing?

Question

I have a full mirror of the Trusty repositories, made with apt-mirror. I keep a backup on another disk by using an rsync command. Whenever I do the backup, I notice that no files are ever deleted. This leads me to believe that new versions of packages are added, index files are modified, but no packages are ever deleted. This seem to be backed up by the size growth of the initial repository download by apt-mirror.

Are the repositories only ever added to continuously?

Edit: Comments suggest that the lack of deleted files is due to an error with usage the rsync command. This is not the case. This is the command I use:

rsync -av --delete --log-file=/home/user/test_mirror_update_20160610.txt /path/to/raw_mirror/ /path/to/test_mirror/ &

Answer 1

Yes, unless you change distro.
Packages might be removed when moving from Trusty to Xenial (for example).

Note that usually no new software is added to the repo on the same distro (or maybe on point-version, like 14.04.4), but just the new versions of software already there.