How do you know? Not doubting you, just curious as to how you figure out if a request is from a bot or not.
Well, obviously, a sneaky bot is a sneaky sneak and acts like a person. But conversely, people act in a way that could be like a bot if anyone casually looked at them - mass downloads, no theme or meaning to content. In general, however, it's all pretty much people. Millions of people a day.