text: there were 18 of these in 2005.  to do with nature?   there were more than 18 hurricanes in 2005. however, there was a report released in science magazine in september of 2005 that the number of category 4 and 5 hurricanes has nearly doubled (i believe the rise was actually 80%) over the past three decades, to an average of 18 per year. that doesn't exactly answer your question because the year wasn't over when that number came out, and it is an average, but that number made a lot of headlines. i think that annual average number of hurricanes may be your answer.   this is important because this is being tied to effects of global warming, and the threat of things getting even worse.