This would also help prove the "definition" (US) of broadband at the time the change was made, but I can't find the FCC release for the 2010 decision.  The 2015 decision was in January, but that really doesn't mean much at all for the 2010 decision.  Regardless, it seems reasonable to assume that broadband would realistically have fallen somewhere between 128kb/s and 4Mb/s at the time of this release.