Dark data is unused information that often sits idle—about 55% of enterprise...

https://wiki-global.win/index.php/Why_Do_AI_Agents_Cost_More_When_There_Is_Too_Much_Dark_Data%3F

Dark data is unused information that often sits idle—about 55% of enterprise data remains dark. This dormant data poses a real breach risk if hacked and adds unnecessary storage and backup costs, which can exceed $2.5 million annually