They weren't even up to a quarter of the Orion Spur/Arm by Picard's day. Maybe that much had been charted, but physically explored?
Of course, between the Bajor-Idran Wormhole and Voyager's misadventures, that "quarter of the galaxy charted" boast would likely have become fact.
Of course, between the Bajor-Idran Wormhole and Voyager's misadventures, that "quarter of the galaxy charted" boast would likely have become fact.