What would you use "I saved X lives" to mean if not "compared to what I would have done otherwise, X more people are alive today"?
(I don't at all like the implied precision in giving a specific number, though.)
There are two issues here.
One is tracking of individual contributions. When a charity says "A $5000 donation saves one life" they do not mean that your particular $5000 will save one specific life. Instead they divide their budget of $Z by their estimate of Y lives saved and produce a dollars/life number. This is an average and doesn't have much to do with you personally other than that you were one data point in the set from which this average was calculated.
"I contributed to the common effort which resulted in preventing Y deaths from mala...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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