The majority of all sessions missed during the week of 10 May to 14 May were due to untimetabled sessions for non-compulsory school - age pupils (code X) and illness (code I).
Roedd mwyafrif yr holl sesiynau a gollwyd yn ystod yr wythnos rhwng 10 Mai i 14 Mai oherwydd sesiynau heb eu rhaglennu ar gyfer disgyblion nad ydynt o oedran ysgol gorfodol (cod X) neu salwch (cod I).