Google hasn't stated how many units they have sold, unfortunately. There was a post on XDA developers from a guy claiming to work at the US UPS shipping center

Google hasn't stated how many units they have sold, unfortunately. There was a post on XDA developers from a guy claiming to work at the US UPS shipping centers that stated that Google shipped out 17,000 units for the US launch (http://forum.xda-developers.com/showpost.php?p=34430979&postcount=21493 http://forum.xda-developers.com/showpost.php?p=34430979&...). Whether that figure is accurate or not is anyone's guess.