The data for this period covers nine months of the coronavirus (COVID-19) pandemic as well as three months prior to the start of the pandemic, and therefore should be treated with caution.
Mae'r data ar gyfer y cyfnod hwn yn cwmpasu naw mis o'r pandemig coronafeirws (COVID-19), yn ogystal â thri mis cyn dechrau’r pandemig, ac felly dylid ei drin yn ofalus.