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

https://web-wiki.win/index.php/What_is_Data_Curation_and_How_is_it_Different_from_Data_Classification%3F

Dark data is all the information companies collect but never use—between 60-80% of stored data often sits inactive. This unused data adds clutter, increases storage costs, and can hide risks like compliance issues