There is another thing to remember about statistics. When you take the total number of incidents in a large population and then distribute it across the entire population as a percentage, you can get very misleading results if you try to use that percentage as a probability.
For example, let's pretend (I don't have actual numbers) that 100 American men die of a heart attack while shoveling snow each year. We can divide that number by the total number of American men and determine that on average, every American man has a certain percentage likelihood of dying of a heart attack while shoveling snow. In reality, people living in Florida have zero chance of dying while shoveling snow, and people living in Minnesota have a much higher probability.
In Scuba, we know that the likelihood of getting decompression sickness on a dive is incredibly small, rounding off to 0%. For the vast majority of divers, though, the probability is even less than that. There are divers who push the limits and are on the edge frequently. World famous diver Richard Pyle, whose dives are often between 300-400 feet deep, has had two very serious cases of DCS. Among the divers I have dived with who do very deep dives at high altitude, I know of 6 DCS cases, yielding a percentage far above that probability. In contrast, people who do all their diving in the 30-35 foot depths of John Pennecamp State Park in Florida have pretty much no chance of ever getting DCS.
I will concur that statistics can be manipulated to say a lot of things.
We don't know how many divers are actively diving in the world, so it's impossible to get truly accurate percentages regarding the accident rate, death rate, and which demographic is most susceptible.
The numbers that are available does state that the incident rate goes up with age, my guess is due to heart disease. Having listened to too many speakers, chamber techs, symposiums, etc...one can only discuss these topics with a bit of humor because we are all at risk. Usually, the ones of the end of the spectrums---the true novices with only a few dives and the true professionals with thousands of dives statistically have the greatest risk.
"Death doesn't just take someone it misses someone else." Whether, they call it 'unexpected DCI', 'unpredictable DCI', 'undeserved DCI', the reports are clear, you don't have to be a daredevil diver to suffer an injury, or a deep diver, or a multiday diver, wreck diver, nitrox diver, computer diver....etc.
The numbers change from year to year, I feel on average, and these are not clear cut, that about 1000 divers per year suffer symptoms of DCI, and about 100 divers per year will have a fatality perhaps triggered by an event that occured while diving, perhaps unrelated to any known health condition or error on anyone's part. While these are just averages...If you collected the info from only what DAN knows of the last 10 years, I'm willing to bet it's pretty close.
So, whatever the percentages, people are still suffering and there's risk. If there was no risk, we could move to have all Key Largo operators conducting relatively shallow water dives, do away with Waiver of Claims, Indemnity Agreements and Assumptions of Risk, plus have pay less for liability insurance.....
Why are any of us teaching in cold water below 40 feet?
