Excellent plan for education! I don't have any stats about emergency care needs of hypos vs hypers, though if someone takes the trouble to look up that information I'd be interested in hearing it too! My guess from anecdotal reports is that hypos are more common. Some people on here have reported having multiple occasions where they needed emergency care for hypos (though I still think it's the minority in diabetics, especially since advances in testing, cgm's etc). Most people report having DKA just on diagnosis (and not all of us had that experience) Again there are exceptions with people that had DKA more than once in their diabetic lives but most of the time again we can catch it and treat highs before they get that dangerous. So bottom line my guess is that hypos are still more commonly emergency situations.
Having said that, I think it's important to educate people about the difference. I think the public just thinks "diabetic coma, give them sugar". Couple problems with that: 1. You don't try and force sugar down the throat of an unconscious person, many people have died from choking. 2. if they're in DKA that is the last thing they need. I think the reverse is true as well: "diabetic coma, give them insulin" - again the last thing a person in a severe hypo needs! So education is important.
On the third question: My take on it (again looking at anecdotal evidence only) is that once you are in DKA you always need medical care. It is often possible to correct highs and get them down with diligent attention and effort before it gets that far. But my understanding is that DKA is always a medical emergency.
If someone does come up with some stats to answer your question, my follow up question would be what countries those stats are taken from? I would think in developing countries where good diabetes care is unavailable or financially out of reach of most of the population, the picture would be much graver. With lack of regular and reliable insulin, lack of testing equipment let alone Cgm's and pumps, I think DKA would be, unfortunately much more common.