The official Mafia term for "associate" means somebody is "on record" with a wiseguy, like Donnie Brasco with Lefty, also the media definitely uses it more loosely. I personally believe that when the FBI uses the term associate, they are referring to guys that are "on record," meaning they work for the mob and are under the mob's protection. I don't think this really applies to bikie gangsters or members of other organized crime units, and I've never seen a bikie referred to as a Mafia associate.
Also, in today's day and age, local politicians and businessmen would make up a very small percentage of the Mafia associates referred to in FBI figures, simply due to the fact that the Mafia's grip on legitimate industries has really loosened over time. I would say the 750 associates in the Gambino Family are "on record" guys. It wouldn't be an exaggeration to say a soldier could have six guys under him. Some Italian, some not. Some might be proposed for membership, most not. When we see big, bread-and-butter, street-level busts, the number of associates far outranks the number of made guys.