the numbers you've got there are just for the atlantic. they don't take into account the pacific and indian ocean basins. the climatological base period you're using has an inherent upward bias over all time periods prior to it (global satellite coverage has only been around since the 60s/70s period). comparing the windspeeds assigned to hurricanes in the 1970s versus the early 2000s is like comparing apples and oranges, as the flight-level to surface conversion ratios used are different.
clark just demonstrated, to a lesser degree, how you can take this data and squeeze an entirely different result out of it, by being selective or not taking into account glaring systematic inconsistencies in the data. the data quality issue alone eats up any argument that has been made about human influence on hurricane activity. a little familiarity with the existing database of hurricane activity makes you aware that it isn't really accurate enough for long enough to make any meaningful trend assumptions out of... even the AMO cyclical nature is hard to resolve cleanly. right now the HRD folks are slowly working their way up through time to the modern record... so within a few years the existing record used for the research will be tweaked anyway, and likely have storms added or adjusted upward in the early part of the analysis period used. the first time i saw the emmanuel paper and webster i immediately saw the flaws, but knew it would be all over the media (perfect timing, in sync with katrina) and expected to see it on all the banners of people convinced the environmental apocalypse is at hand. al gore even added predicting hurricane katrina to his list of lofty achievements. take that, internet.
point to take home is, yes, people have created an upward trend in hurricane activity... on paper.
HF 1750z15june