Norman- I'm not really concerned with deaths from disease, shipwreck, etc. I mean only the real butcher's bill- those whose deaths contributed to the defeat of France (a very imprecise instrument, I agree, but a good indicator.) You have a figure of 32,000 British battle deaths 1804-1815. I'd be interested to hear what your sources are. They're rather higher than mine. After Waterloo, Lord Henry Temple (the future Lord Palmerston), in his capacity as Minister at War, gave the Commons an account of British military activities from the engagement at Valenciennes (July 1793) to the taking of Peronne (a week after Waterloo). In 22 years of warfare (including the War of 1812) , the British Army lost 920 officers and 15,214 other ranks, the Navy lost 3,662 men. Less than 20,000 KIA. Having read the books and watched the tv series, Hornblower, Sharpe, etc, these figures came as a shock to me (I found them in Jasper Ridley's life of Palmerston.) I suddenly realised how minor Britain's direct military involvement in the French Wars was, as opposed to,say, Austria. The point I'm trying to make is that Britain, with only limited involvement in Europe, tended naturally to overstate the value of its armed contribution. It saw itself as an overall arbiter, not realising that in fact it was a peripheral power. In fact, just like America in 1918. To me the importance of American forces in Europe is greatly overstated. It's one of these myths like the crucial role of the tank or the unparalleled iniquity of Versailles. What finally broke the will of the German High Command was events in the East, not West, the collapse of Germany's allies.
GW- I don't think American entry had anything greatly to do with French Army morale. In fact the great mutinies occured after America entered the war. What kept the French going was the implied promise that there would be no more pointless offensives like Nivelle's.