Back in my health class in high school, the teacher did an individual poll about this kind of thing. He would tell people to raise their hands while asking "how many of you eat around x amount of calories?"
The skinnier girls ate around ~2,000 calories when called on. Average sized and overweight girls raised their hands around 2,500 calories and more when called on. One ate 4,000. Even when I was borderline obese, I never even ate 4,000 a day, JFL.
I think I ate the least amount of calories out of everyone in the class at the time. I was desperate to lose weight, and was eating a calorie count barely touching four digits.
I would say that the average American woman eats around 3,000 calories a day, based off of that.