The proportions of new dwellings built on previously developed land by local authority area are published in the Department's Land Use Change Statistics Live Table 213. This table can be found at
http://www.communities.gov.uk/planningandbuilding/planningbuilding/planningstatistics/livetables/landusechange/
The statistics are shown as for averages for the following periods 1992-95, 1996-99, 2000-03, 2004-07. Estimates for individual years at district level are not regarded as reliable.