Mae’r model diweddaraf yn ffrwyth cyfnod hir o adolygu a gwella parhaus a arweiniodd at leihau nifer yr asiantwyr sector cyhoeddus o 8 i 3 yn 2005 ac o 3 i 2 yn 2012.
The current model is the outcome of a process of continuous review and improvement which resulted in the number of public sector agents being reduced from 8 to 3 in 2005 and from 3 to 2 in 2012.