By the Office for National Statistics (ONS), to publish aggregate statistics related to the economy, population and society at UK, Wales, and local levels.
Gan y Swyddfa ystadegau Gwladol, er mwyn cyhoeddi ystadegau crynswth mewn perthynas â’r economi, y boblogaeth a chymdeithas ar lefel y Deyrnas Unedig, Cymru a lefel leol.