ONS and ADR Wales estimates suggest that between 5% and 6% of children could not be found in the education data in March / April 2021.
Mae amcangyfrifon y SYG ac YDG Cymru yn awgrymu na ellid dod o hyd i rhwng 5% a 6% o blant yn y data addysg ym mis Mawrth / Ebrill 2021.