When Your Digital Life Vanishes

Unfortunately it doesn't go into depth as to how much success is had with flash memory, such as sd cards, percentage wise, for example snafu sd cards and thumb drives where free recovery software has already failed finding any of the older files.

TLDR in case the original headline is unhelpful - This talks about a company that recovers data lost from digital devices like phones, hard drives from computers and vehicles and several customer stories.