Among what populations is it near universal? I grew up in an upper-middle class bedroom community, and I only had to get first aid certified in order to be a lifeguard at a local pool. That was just about a decade ago, and I’d be hard-pressed to do anything other than apply a cold compress and perform the Heinrich maneuver now. My father-in-law was a trained physician overseas but became a pharmaceutical researcher when he came to the US, and the last time he was in a situation where he had to perform CPR, he had no idea what to do. I doubt more than 20% of American adults would be useful in a serious casualty situation.