Nearly always 37.5% or 40% aren't they? At least the ones in this country. I can see that it is to do with certain regulations http://en.wikibooks.org/wiki/Bartending/Alcohol/Spirits but it seems unlikely that it's accurate. Are you trying to tell me that some of them aren't 39%? Or are they tweaking some to make them hit the targets? Maybe they would taste better at 41% but we are made to suffer.
What the fuck is going on?