it's (1-p)^24^10, where p is drive failure rate per year (assuming it doesn't go up over time). so at 1% that's about 9% or a 1/10 chance of this result. Not exactly great, but not impossible.

the backblaze rates are all over the place, but it does appear they have drives that this rate or lower: https://www.backblaze.com/blog/backblaze-drive-stats-for-q2-...