How would they show this? The only possibility I can think of is exit polling. Right now, it's possible for say CNN to get good exit polling numbers because they need to hang out at polling stations for only a day. I wonder if they'd still want to do it if they had to spend a whole week camping outside polling places, talking to a much slower trickle of people. I suppose a candidate with a vested interest in these numbers might pay for the service but that could then raise doubts about bias.