I have a cache in my Hides stats that was hidden on 13th July 2016 and archive on 9th March 2017 (GC6NCE1). Not the longest lived cache in the world, it was found 36 times. However, in the stats it shows as zero finds per day. The cache was around for 239 days so, by my calculations, it should show as 6.64 days per find.
This isn't the only cache in my Hides that shows this issue, I have another hide (GC29QY6) that was active from 22nd May 2010 to 9th March 2017 (2483 days) that shows 0 days per find but I think it should be 9.74.