I live in France. I've found that at least cheaper (supermarket) spirits are almost always exactly 40% ABV. You can find stronger if you buy more niche or expensive alcohols like Chartreuse, but the vast majority seems to be precisely 40, unlike say wine or beer which varies more smoothly.
Is there a reason for this? Is 40% the legal minimum to be able to call something whiskey or vodka, for instance? Or am I just flat wrong, and there's no statistical trend towards 40%?
I realize the correct answer may vary from country to country. I'll be happy with an answer covering any "comparable" first world country (let's just say English speaking countries or West Europe, for simplicity).