Margie, You've been looking at the AOML site, haven't you.
...One complication with the use of the 1 min averaging time for the standard for sustained wind in the Atlantic and Northeast Pacific tropical cyclone basins (where the United States has the official World Meteorological Organization tropical cyclone advisory responsibilities) is that in most of the rest of the world, a 10 min averaging time is utilized for "sustained wind". While one can utilize a simple ratio to convert from peak 10 min wind to peak 1 min wind (roughly 12% higher for the latter), such systematic differences to make interbasin comparison of tropical cyclones around the world problematic...
http://www.aoml.noaa.gov/hrd/tcfaq/D4.html

http://www.warnercnr.colostate.edu/class...sion_charts.pdf

http://www.csgnetwork.com/windspeedconv.html