This excerpt taken from the HOG 8-K filed Jan 22, 2010.
Heavyweight Market Data
1 - United States industry data includes 651+cc models, derived from submission of motorcycle retail sales by each major manufacturer to an independent third party. This data is subject to revision and update. As of the second quarter 2009, industry data includes three-wheeled vehicles retroactive to 2008.
2 - Europe data includes Austria, Belgium, Denmark, Finland, France, Germany, Greece, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. Industry retail motorcycle registration data includes 651+cc models, derived from information provided by Giral S.A., an independent agency. Europe market data is reported on a one-month lag. This data is subject to revision and update.