As a result, they changed how they weight the data and re-weighted their estimates for January to June 2020 (i.e. quarters 1 and 2 of 2020) to account for this change.
O ganlyniad i hyn maent wedi diwygio sut maent yn pwysoli'r data ac wedi ail-bwysoli eu hamcangyfrifon ar gyfer mis Ionawr i fis Mehefin 2020 (h.y.