This is a TRT (Transfer Rate test). It is not useful for judging degradation, but the transfer rate looks okay, no major dips, at least it's still perfectly readable.
You should still do a quality test instead. It will tell us about C1, C2 and C3/CU errors. If you see any C2 errors, you should immediately copy the disc, or you'll lose all the precious data on it. If C3/CU errors show up, it's already too late.
Not every drive is capable of quality tests. In that case, just try another drive to scan. (LiteOn and BenQ drives will support scanning with Nero CD-DVD Speed although LiteOn DVD writers' CD quality scans won't tell us much, Plextor drives will support scanning with Plextools.)
Those little cracks can be very nasty. I think you should copy the disc soon, or it might break in your drive at high speeds. We've already had a few users with broken drives because of broken CDs... :iagree:
Anyway, Ritek CD media is still okay, at least compared to their crappy DVD-R...