I recommend using Ookla instead - you know the guys behind "Speedtest.net" - which is a better representation of the Tech audience.
http://www.netindex.com/download/
Results are substantially different, US still gets a pretty bad score but it sure as hell isn't as low as Akamai's speed rating.
Besides I really don't know how the US is ranked before all those european countries - Especially Sweden!!! - which has a remarkably more developed internet infrastructure







