Which sentence is correct?
"I had more customers than usual." "I had more customers than usually."
"More than usual" sounds pretty common, but "more than usually" seems more correct when I think about it. There seem to be more adverb adjective conflicts like this, for example "drive safe" vs. "drive safely", which was explained here: Which is correct: "drive safe" or "drive safely"?Which is correct: "drive safe" or "drive safely"?. Is the rule the same in case of "more than usual"?