Precipitously

"Population dropped to the lowest point in five millennia. State resources declined precipitously. In many strategic and formerly prosperous areas, there were tax revenue losses of 90 percent or more in less than a single lifetime."

"Never will I visit it again; it is a place of evil omen.' After a very brief halt for breakfast we pressed on with such good will that by two o'clock in the afternoon we were at the foot of the vast wall of rock that formed the lip of the volcano, and which at this point towered up precipitously above us for fifteen hundred or two thousand feet."