2013 Nissan LEAF connected to CHAdeMO charger
According to CHAdeMO Association, there are now 633 CHAdeMO DC fast chargers installed in the US. Actually, there are more than 633, but CHAdeMO's updates lag actual installs by a least a few weeks, sometimes even a couple of months.
Of those 633 units, Nissan says that at least 180 are installed at Nissan dealerships throughout the US (our guess is that 80% or more are so are at Nissan dealerships located in West Coast states).
Last tidbit of information is that Nissan is trying hard to get all of those DC chargers on PlugShare, which is a plus for EV owners who predominantly use PlugShare to locate nearby CHAdeMO chargers.
Worldwide CHAdeMO Map (June 2014): 633 CHAdeMO DC Fast Chargers In The U.S., 3740 Worldwide