Powys (-230) and Bridgend (-460) experienced the lowest levels of cumulative UPC in Wales in the period mid-2012 to mid-2021.
Gan Bowys (-230) a Phen-y-bont ar Ogwr (-460) oedd y lefelau isaf o UPC cronnol yng Nghymru yn y cyfnod canol 2012 i ganol 2021.