How do I tell how many people have booked a flight

[frost5000]

I'm trying to decide whether to book my airfare now (at considerably higher rates than last week) or to wait it out for a better deal. I read a post that said to book if the flight is more than halfway full, as there prob. won't be any more discounted fares at that point, but if there are you could try and get a voucher - otherwise it's better to try and "wait it out" for the possibility of better fares. My question is how do you tell how many seats are already taken?

[Cruella102]

Some of the airline websites have seating charts that you can use to pick out your seat. I know that Delta and American have this but not sure of the others. When you click on it you can see how many available seats are left.
Or if you purchase through a travel agent they certainly should be able to tell you.