At least that was the case when I looked at kickoffs from the 35 following the 2006 season. In D1A-only games, and excluding kickoffs of less than thirty yards (possible on-side kicks), there were 36 TD returns and 55 fumbles lost (two lost for safeties, three lost for kicking team TDs). Overall fumbles were four times as common as TD returns, but most fumbles were recovered by the receiving team.
Excluding touchbacks, returns for TD slightly increased as a percentage of plays as kickoff length got longer.