If you know more information, you can always change your estimates. Even if you're a surfer in a "sharky" place, what percentage of those are there at the same

If you know more information, you can always change your estimates. Even if you're a surfer in a "sharky" place, what percentage of those are there at the same time as a shark? What percentage of those are chased by a shark? Bitten by a shark? If you're not one of the few that actually get bitten, then you're safe from death.