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

https://wiki-canyon.win/index.php/How_Do_Sensitive_Data_Scanners_Work_on_Unstructured_Files%3F

Dark data is all the information companies collect but never use—often 60-80% of their stored data. This inactive data costs businesses an average of $2.5 million a year in storage and management expenses