Dark data is the information your business collects but never uses—often 55% of...

https://foxtrot-wiki.win/index.php/Does_Dark_Data_Increase_the_Cost_of_a_Data_Breach%3F

Dark data is the information your business collects but never uses—often 55% of stored data. This unused data wastes storage and backup resources, costing millions annually, and increases risk by expanding your ransomware and breach exposure