“I don’t know,” he replies, handing her the cup. "More than ten, less than... could be twenty, could be fifty. Could be more, but I think I’d have noticed more."

With a shake of his head, he adds, "Everyone thought any old stories were stupid. Things have changed." And then, "I thought we all knew what we had, but I was wrong.”

He means: with the dragons keeping the cities relatively stable, until they couldn’t anymore.