As of December 31, 2019, Backblaze had 124,956 spinning hard drives. They take a look at the failure rates of those drives.
The total AFR for 2019 rose significantly in 2019. About 75% of the different drive models experienced a rise in AFR from 2018 to 2019. There are two primary drivers behind this rise. First, the 8 TB drives as a group seem to be having a mid-life crisis as they get older, with each model exhibiting their highest failure rates recorded. While none of the rates is cause for worry, they contribute roughly one fourth (1/4) of the drive days to the total, so any rise in their failure rate will affect the total.
For the details, check out the Backblaze site.