The term "skyscraper" is reserved for buildings at least 10 floors in height. Research over the last 40 years has shown that the number of floors of newly-built skyscrapers has a mean of 50 floors and a standard deviation of 10 floors. If nothing is known about the shape of the number-of-floors distribution, what percentage of the newly-built skyscrapers exceeded 80 floors? At most 11% At most 5.5% Approximately 0% At most 25%