What manufacturer makes the most reliable hard drives?

Backblaze, which is a cloud storage company, shared health statistics for about 60.000 hard drives with more than one billion hours in service. Their storage center contains hard drives from these manufacturers:

• HGST
• Seagate
• Toshiba
• Western Digital

After analyzing the failure rates of all the disks for each manufacturer during 2014, 2015 and 2016, they came up with the following graph:

Looking at the results, it's clear that HGST has the least amount of failure rates, therefore has the most realiable hard disk drives. 

Note: The above results should be taken with a grain of sault since the data presented is about specific disk models and cannot be used as a general indicator for the reliability of the disks produced by a manufacturer.

Source: https://www.backblaze.com/b2/hard-drive-test-data.html