This dataset provides 2011 Census estimates that classify usual residents aged 16 and over in Wales by ability to speak Welsh, by year last worked and by age. The estimates are as at census day, 27 March 2011.

This information helps public bodies to understand the extent to which the Welsh language is used and, therefore, to meet their statutory duties under the Welsh Language Act 1993. It is also used for policy development and monitoring, and provides data for the allocation of grants to support the Welsh language.

In order to protect against disclosure of personal information from the 2011 Census, there has been swapping of records in the Census database between different geographic areas, and so some counts will be affected. In the main, the greatest effects will be at the lowest geographies, since the record swapping is targeted towards those households with unusual characteristics in small areas.

More details on the ONS Census disclosure control strategy may be found on the http://www.ons.gov.uk/ons/guide-method/census/2011/census-data/2011-census-prospectus/new-developments-for-2011-census-results/statistical-disclosure-control/index.html[Statistical Disclosure Control] page on the ONS web site.