Methodology and quality of data You can download the methodology and quality of data used in this release (pdf, 343KB)PreviousBack to report Was this page helpful? Yes No Yes, but Select a reason It wasn't detailed enoughIt's hard to understandIt's incorrectIt needs updatingI'm not sure what I need to do nextThere's a broken linkOther Your comments Your feedback will help us make improvements on the site. Please don't provide any personal information.