The information requested falls within the responsibility of the UK Statistics Authority. I have asked the authority to reply.
Letter from Stephen Penneck, dated December 2011
The table shows estimates for part a) and relate to the period January-December 2010. The estimates are derived from the Annual Population Survey (APS) and are not seasonally adjusted. An asterisk indicates that sample sizes are too small to provide reliable estimates for a particular parliamentary constituency. The table will be placed in the Library of the House.
For part b) it is not possible to provide reliable estimates for parliamentary constituencies because the sample sizes are not sufficiently large enough.
As with any sample survey, estimates from the APS are subject to a margin of uncertainty as different samples give different results.