> In Q1 2013, average connection speeds on surveyed mobile network operators ranged from a low of 0.4 Mbps to a high of 8.6 Mbps. Only nine operators demonstrated average connection speeds in the aforementioned broadband category while 64 more operators showed average connection speeds above 1 Mbps.
http://thenextweb.com/insider/2013/07/23/akamai-average-inte...
My 80% number was hyperbole, but I do think the data supports that on world-wide average, mobile connections are drastically lower, and so making assumptions about a file size downloading quickly on fast broadband is ignoring an increasingly important part of the web traffic, which are years behind wired connections in terms of speeds.