The year Hurricane Katrina struck Louisiana, wreaking havoc in New Orleans, had the highest number of storms over the Atlantic basin (28), of which 15 were categorized as hurricanes (cat. 1-5), of which 7 were classified as major hurricanes (cat. 3-5). Four of those tropical cyclones made landfall over the U.S. in 2005.
According to the Hurricane Research Division (HRD), storms that have made landfall over the U.S. have been well documented since 1900. Storms that have stayed out at sea, over the Atlantic basin, have been better tracked since 1966, when daily satellite imagery was made available to the National Hurricane Center (NHC).