This is the average speed for the Netflix streams, not the average speed of the internet connections. So if their highest bitrate stream is 5 Mbps for example,

This is the average speed for the Netflix streams, not the average speed of the internet connections. So if their highest bitrate stream is 5 Mbps for example, that is the maximum you could see on those graphs. These ratings reflect the average performance of all Netflix streams on each ISPs network. The average is well below the peak performance due to many factors including the variety of encodes we use to deliver the TV shows and movies we carry as well as home Wi-Fi and the variety of devices our members use. Those factors cancel out when comparing across ISPs, so these relative rankings are a good indicator of the consistent performance typically experienced across all users on an ISP network.