(a) Includes estimated figures for Cardiff, as the authority was unable to provide data on assessments containing category 1 and 2 hazards during the year.
Mae pob siart yn dangos y blynyddoedd yr oedd pob asesiad ar waith, ac eithrio blwyddyn 2019/20 am nad oedd digon o ddata ar ei chyfer oherwydd y tarfu a achoswyd gan COVID-19.