Don't have my (previously) main rig boot drive to read the info off at the moment, but I do remember that it's at around 94% after 10 years of active use. (240GB Size)
A storage drive that was used in that main rig, sits at:
97%
Total Host Writes: 17582 GB
Power On Count: 4915 Counts
Power On Hours: 33800 Hours
I had the page file and any and all alterable temporary storage folders be moved to the RAMDrive I employed on that rig, which reduced the amount of writes that were needed on the drives. Any files, etc, are stored on a NAS instead. So the drives were only ever hit by save game storage or program installations and uninstallations/repairs.