Schools’ data are derived from the Pupil Level Annual School Census returns and STATS1 returns supplied by schools open on Census day in January each year.
Caiff y data eu casglu o ysgolion cynradd, uwchradd ac arbennig a gynhelir yn CYBLD mis Ionawr ar ôl y flwyddyn academaidd y digwyddodd y gwaharddiadau ynddi.