Planet Money covered it recently (http://www.npr.org/blogs/money/2013/02/15/172108399/episode-436-if-economists-controlled-the-borders http://www.npr.org/blogs/

Planet Money covered it recently (http://www.npr.org/blogs/money/2013/02/15/172108399/episode-436-if-economists-controlled-the-borders http://www.npr.org/blogs/money/2013/02/15/172108399/episode-...). Time varies based on country of origin. Each country is allocated a fixed number of spots, and these spots of of similar size for all countries. So, if you're coming from a small country (i.e. Iceland) it's easy. Coming from India/Mexico, then you'll have to wait a while..