Dark data is the unused information stored in your systems, often making up 55%...

https://speedy-wiki.win/index.php/Is_It_True_55_Percent_of_Enterprise_Data_Is_Dark%3F_Exploring_Dark_Data_Statistics_in_2025

Dark data is the unused information stored in your systems, often making up 55% of all data. It can expose your organization to ransomware attacks and breach risks since it’s unmanaged and unmonitored