Re the concern a few have expressed about converting Optimum Pint Level to Optimum Liter Level, in my neighborhood the common expression is "the PBL" - for Proper Buzz Level - in recognition that even for any one individual, the amount and required rate of consumption may vary depending on the circumstance and occasion at hand.
The arguments about which beer/ale/... is stronger will probably never end, at least until we all are licensed as chemists. In the US, in most states, the accepted practice for distilled spirits is that the "proof" is 2 times the percent-by-volume alcohol content. Even this is not an "iron-clad" definition, since different jurisdictions use slightly different methods of measurement; but for "talking purposes" in the US, 100% pure ethyl alcohol is "200 proof," and in some jusrisdictions you can buy it that way, although most places the "maximum" offered for sale is 180 proof (90% by volume). Most popular distilled stuff runs about 90 proof, or 45% alcohol by volume.
In the US, "cereal malt" beverages, which includes beers and ales, are generally regulated based on the "percentage of alcohol by weight." There is no simple way to convert "percent by weight" to "percent by volume" since the conversion depends on the density of the "other stuff" in the mix - and it does vary.
And may also be noted that the "standard" 12-oz can or bottle is 12 fluid ounces which is a measure of volume, not of weight - so you can't readily compute the "absolute amount of alcohol" in a can, unless you've got a good balance. The real problem, though, is that in most jurisdictions, there is no "label" strength. Beers and ales are not generally labelled as to strength - so all you've got to go on is your bartenders guess, and he's unlikely to know any more than you do. In some jurisdictions, where there are limits on what may be sold, some containers may be marked with a "does not exceed 3.2 percent by weight," (or 2.8% in a very few places) but that doesn't mean that it is 3.2% - only that its less than that.
It's a fruitless, and useless, argument, since no matter how strong (or how weak) your favorite is, you can always drink enough to get to your PBL, and you can always drink too much if you choose to do so.