It is always a challenge to carry out such surveys and the previous iteration required some late intervention to ensure that Wales was adequately represented.
Mae bob amser yn anodd cynnal arolygon o'r fath ac roedd angen rhywfaint o ymyrraeth hwyr ar yr arolwg blaenorol a gynhaliwyd er mwyn sicrhau bod Cymru wedi'i chynrychioli'n ddigonol.