Might be a month late on this one, but still an interesting read. This is a report from Colliers International with all the top Global Retail Centres and their rates. Top retail corridors in the US including 5th Avenue and Madison Avenue in New York saw decreases in lease rates of $250 and $350 per square foot per annum respectively.. which is a huge drop.
See the attached PDF article for more info an comparisons of the most expensive retail rents in the world: