EDIT: here's the link, which is different from what it used to be because I changed the folder structure of my dropbox:
<a href="http://dl.dropbox.com/u/15543016/lem/Lemmings Levels.xls" class="bbc_link" target="_blank">http://dl.dropbox.com/u/15543016/lem/Lemmings%20Levels.xls</a>
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I have no idea if this has been done already, but I've been compiling all the levels into a spreadsheet for perusal. Source for Lemmings 2 and Holiday Lemmings was tle.vaarties.nl ; source for Genesis lemmings was half playing it through myself and half harvested from Planet Lemmings (or whichever one they get the screenshots from in the review thread).
I double checked your work - or rather,
some of it - and at least two of those numbers are wrong. In the Polar level "Snowed In !", Ernst (of TLE) was, in fact, able to beat David Crooke's record of only losing three, by losing only
two - but for some strange reason (correct me if I'm wrong!) you can lose up to FOUR can still get Gold. Perhaps they screwed up (saving all but two is easy enough), but I verified it, and you can, too.
I also double checked We're Coming Home, of the Circus levels, and you can lose up to 2 before losing the Gold.