PlayStation Move has been available in Europe and North America, and the one month the device has been on sale in Japan, the core Move controller has sold 4.1 million units.
Considering the PS3 has sold 41.6 million units to date, that means one out of every ten homes that has Sony's gaming console now also houses a Move. Or, since the Move really works best with a second controller in hand, it could mean that one out of every twenty homes owns two of the devices. Or, perhaps less likely, one out of every thirty PS3-owning families contains three Moves, for their freakish, three-armed children.
Update: There seems to be some confusion as to whether this figure represents the number of Moves actually purchased by consumers or sold to retailers. Though the U.S. press release revealing the sales posted after the jump explicitly says "sold," the Japanese press release mentions "the quantity delivered to the dealer" in a footnote. We've contacted Sony for clarification.
Update 2: A Sony representative explained that the 4.1 million actually represents Move units shipped to stores, adding "While we don't disclose our exact sell-through number, the key is that our retailers continue to ask for more Move units and are taking every unit we can supply them with based on their sales." Which, you know, would have been a cool thing to put in that press release, we think.