After over a decade of bringing you the latest Diablo news and builds, DiabloFans will be shutting down on March 21st, 2019. On this date, we will archive the site in an effort to preserve the history. Thanks for your patronage throughout the years.
As other players have noted, followers give you 20% of their total adventuring stats which include Magic Find, Gold Find, and Experience. So, if the Hellfire Ring is giving your follower +35% XP bonus, then you end up with +7% XP bonus from it .