The 2021 Census asked usual residents to report if they had a long-term physical or mental health condition or illness, lasting or expected to last 12 months or more.
Gofynnodd Cyfrifiad 2021 i breswylwyr arferol adrodd a oedd ganddynt gyflwr iechyd meddwl neu gorfforol hirdymor neu salwch, a oedd yn para neu yr oedd disgwyl iddo bara 12 mis neu fwy.