Census is 'hitting target'.
Questionnaires were sent to 26 million households at the beginning of March to fill out on Census Day, March 27, or as soon as possible afterwards.
A period of visits by 29,000 officials to properties who had not yet filled out the national survey - carried out every 10 years - has just ended.
Giving evidence to the Public Administration Select Committee, chairman of the UK Statistics Authority Sir Michael Scholar said it appeared to have been a success.
"The Office for National Statistics is cautiously optimistic that over 90 per cent of the forms which were sent out have been returned or will be in the coming few days."
Twin targets of an average 94 per cent return rate with no single local authority area returning less than 80 per cent of forms were also expected to be met, he suggested.