Data for the years requested are available on the civil service website. The latest available data are as at April 2005 and these, together with previous years' data, can be found at the following website addresses:
http://www.civilservice.gov.uk/management/statistics/publications/xls/report_2005/table_p.xls for data as at April 2005,
http://www.civilservice.gov.uk/management/statistics/publications/xls/disability_apr04_4nov04.xls for data as at April 2004, and
http://www.civilservice.gov.uk/management/statistics/archive/index.asp for previous reporting periods.
Declaration of a disability is voluntary.