Dark data is the huge chunk of company info—often 55% or more—that sits unused...

https://jaspersmasterinsights.opalvector.com/posts/the-fastest-win-to-cut-storage-costs-from-dark-data

Dark data is the huge chunk of company info—often 55% or more—that sits unused and forgotten. It wastes up to $2.5 million yearly on storage and adds risk by cluttering security checks