I didn't find an answer in there except for an estimate concerning "living vets" since WWIIand compared to what - living Americans? If you include back to WWII vets, then you would have to figure out how many Americans were alive during WWII, and the amount of deaths and births to come up with a fairly accurate figure for today, based on the "what % of Americans are veterans?". I say it's much harder to to determine, over the course of the US - some 230 years, the total official number who have ever served "officially" in a ratio to the total number of people who have lived in the US since 1787. You would have to add in all the miltias, state and local as well.
The question is interesting, and the answer given is misleading. I think the number is probably a bit smaller than that article stated.
Whatever, thank you for serving, and I'm about to embark to my local Publix -"Where shopping is a pleasure"! with me retired ID to get 10% off my purchase today.