fashion and architecture

[query]

fashion and architecture has become a much debated topic , what are peoples thoughts on the subject and does anyone know how much of the built world is comprised of retail ???
Rem Koolhaas stated once it was 40%..i need a source for this , as I need this piece of info for my thesis
so if anyone can give me a reference or source for info like this I would appreciate it , that figure may not be correct so i need to find out how much is retail
my thesis if focusing on new retail , how fashion and architecture have fused. any thoughts negative and positive

thanks