I was part of an effort at my last job to archive some of the source code for our oldest projects(from the 90s), they were all on CDs stored in a vault with an external storage company, we retrieved the boxes and found that 1 in 5 discs didn't read at all. The blue verbatim discs had a 100% success rate, but any disc with that green hue underside was a toss up whether it would read or not. Interestingly though, over hundreds of discs I found that either the disc read and would rip correctly all the way, or it wouldn't work at all in the first place.