I asked this question recently with following answer from Support:
Information about lab caches can not be retrieved via Groundspeak's API which is what we use to fetch information about caches. This means that we can not make statistics about lab caches since we can't get information about them. If Groundspeak changes their API to include lab caches we can most likely include statistics about them as well, but not before that.
For me, it was sufficient, it depends on GroundSpeak.