Uk games retailer markups

There seems to be load of smart people lurking around here so it might be a good place to throw this one in. Just out of curiosity does anyone know what percentage of the price of a game do retailers such as Electronic Boutique/Virgin/HMV get?

For example if it`s £30, how much of that is going to the shop?

Not much of a markup on £30. The manufacturors RRP will be 39.99-49.99. The high street and online store competition is pretty brutal.