The Cabinet Office, on an annual basis, publishes a report to Parliament on the performance of departments in replying to Members/Peers correspondence. Information relating to 2008 will be published as soon as it has been collated. The report for 2007 was published on 20 March 2008, Official Report, columns 71-74WS. Reports for earlier years are available in the Library of the House.
In respect of other correspondence and emails from the public, only non-individually addressed correspondence is managed centrally. The information requested cannot be obtained save at disproportionate cost as to do so would require gathering information from every official in the Department.