For a real-life view, an organization that has only 1,000 of these drives among all systems can expect a drive failure about every two months. A nicer way of looking at it is that odds are your RAID with 14 drives won't have a failure for over 10 years.
The odds they quote are only accurate for maybe the first year. Disk drives are like light bulbs. They all burn out. It's likely a 14 disk RAID will have some drive failures in less than 10 years, just not during the first year.
Disk drive makers have been sued many times for saying a megabyte is 1,000,000 bytes instead of 1,048,576. Technically they are correct because mega means million. At some point a lawyer will make a business suing about MTBF claims.