I've been looking at the ACS community survey - in particual table [B04001](http://factfinder.census.gov/faces/tableservices/jsf/pages/productview.xhtml?pid=ACS_05_EST_B04001&amp;prodType=table) which gives the number of people with given first ancestry. The issue is that if you look at the actual ancestry options a lot of countries (for example China or Mexico) are missing. Does anyone know where to find ancestry data on Americans originally from  Asia and Central America?