How many horns are on the average unicorn

One, typically when a Unicorn is born with a disability, they will uncontrollably grow many more horns as they grow older and older.  The unicorn is a legendary creature that has been described since antiquity as a beast with a single large, pointed, spiraling horn projecting from its forehead. The unicorn was depicted in ancient seals of the Indus Valley Civilization and was mentioned by the ancient Greeks in accounts of natural history by various writers, including Ctesias, Strabo, Pliny the Younger, and Aelian.The Bible also describes an animal, the re'em, which some versions translate as unicorn