The reason why dead people started to be buried six feet under is an outbreak of the plague in 1665 in London. The disease was so contagious that the mayor decided that that was going to be the standard depth of burials in order to avoid further infections.
Nowadays, burials are normally shallower due to the practice of embalming bodies and the use of metal caskets.
Drowning involves suffocating while in water, and 90% of the drownings occur in freshwater. This happens because of osmosis: it’s easier to breathe freshwater and suffocate because the salt prevent the water from getting into the lungs. A person can die from breathing freshwater even hours after being in it.
If you live in the U.S., your chances of getting killed in a transport accident are 1/80. If you live in Europe, the odds are 1/127, although car crashes cause much more fatalities than planes or trains.
Grim Reaper's Little Helper 