The scope of your survey is rather broad spectrum, and isn't necessarily placed in the right forum for the most results. This forum (Firewood, Heating & burning...) will certainly have a large number of candidates for that question, the results will hardly be inclusive of the highest number of positive responses.
Are you after private citizens that use chainsaws regularly? This might be a great place for that survey.
If, however, you are looking for reports of injury or results from among folks that use chainsaws for a living, your results will be markedly different if posted in "Arboricultural injuries" or any of the "Tree care" forums. Foresty and logging will get nearly 100% positive responses, as will Commercial Tree care. Arborist 101, will net lower results, but higher than the firewood forum. Milling and sawmills will also have a rather high positive response rate.
As to your survey, I have never received any stitches as a result of chainsaw contact, but I have been cut a couple of times. With over 35 years of active use, I think that's not too bad. On the other hand I have had several severe injuries incurred by employees, and one fatality. I would venture that everyone in the business would have a positive answer to "got injured whilst using a chainsaw".
I think your survey should be limited to certain types of injury, such as chainsaw cuts requiring medical treatment. If you just wish to get information about injury rates, consider talking to any worker's comp insurer. They have tons of data regarding general injuries associated with chainsaws.
