GD,
If you can get access to the latest Edition of RAF Air Power Review (Winter 2002 edition), it has a piece in it by Col Phil Meilinger USAF (ret.) which contains quite a few casualty figures from various wars. He's using them to demosntrate that the 'vast number of casualties caused by air power' argument is a bit thin...
He cites sources giving the number of dead from wars in the 20th century as between 110 and 170 million (the source for the first figure is 30 years old, though, so is obviously lower than the figure now).
Other figures he cites:
Desert Storm: Green Peace estimated 3000 dead as the result of the air campaign, a figure later revised down to 1,000.
Op Deliberate Force: 25 Serbs killed (according to Slobbo himself)
Op Allied Force: approx 500 dead as part of air campaign (source: Human Rights Watch)
These might help with the second part of your query, since we have fairly accurate accounts of what was used, missions flown, what was dropped, etc.
The Second World War figures vary, since no-one can agree on how many Russians died. When I was a lad, the first reference I saw said between 18 and 20 million; this has now been revised to between 25 and 28 million, and some researchers suggest that it may even top the 30 million mark. It depends upon which sources you look at. The same applies to the missions flown and how much dropped: sources vary, not least because the records of some of the combatants were destroyed or not well maintained.