Dark data is all the information companies store but never use—sometimes 60-80%...

https://cashsbrilliantperspectives.cavandoragh.org/what-does-garbage-in-garbage-out-look-like-in-vector-databases

Dark data is all the information companies store but never use—sometimes 60-80% of it. This hidden data adds up, wasting around $2.5 million a year on storage and management