We published the first estimate on 20 November 2020, published the second estimate on 23 December 2020 and the third estimate on 28 January 2021.
Fe wnaethom gyhoeddi’r amcangyfrif cyntaf ar 20 Tachwedd 2020, yr ail amcangyfrif ar 23 Rhagfyr 2020 a'r trydydd amcangyfrif ar 28 Ionawr 2020.