One good thing about the Church of England is that they publish detailed statistics and financial statements. They have just published a report (they do this annually) on the expenditure incurred by bishops and archbishops. Including the two archbishops, there are 113 of these, made up of 44 diocesan and 69 suffragan bishops.
The total expenditure is £30.2million. this is made up of:
Work of bishops £20.0m
Maintenance of houses and gardens £4.7m
All these figures are broken down for each of the 113 bishops. I suppose that compiling the report must have cost a fair bit. It does seem an incredible amount of money.