Not sure about true data, but i could imagine that cargo vessels are involved in a majority of accidents on sea. They are - fast - like really fast. You cannot outrun them with your sailboat, even with engines. And they won't change course, because they cant. If they turn the rudder, they need to wait for some 2 miles for it to take effect. Suprisingly many sailors don't know that or neglect it.

So next time there is a war, just send dem cargo ships.