The 50-year climatology for tropical cyclone activity in the North Atlantic Basin is 12.4 tropical storms, 6.4 hurricanes and 2.5 intense hurricanes. The accumulated cyclone energy index is 99.2. During the past 25 years the climatology is somewhat stronger numbers...15.3 tropical storms, 7.6 hurricanes and 3.4 intense hurricanes. ACE index is 125.8. Why are the numbers higher?