Someone on digg posted a variant of this question on Quora: “What are the chances of survival of individual chess pieces on average.” In reply, Oliver Brennan, a chess aficionado and computer programmer, posted this answer:

Image credit: Oliver Brennan

Update (25 Oct. 2014): The excellent Ada Swanson interprets this probabilistic chess board as follows (emphasis ours):

The kings have the highest survival rate … because they can’t be taken. Rooks also tend to be hardy because they spend a lot of time at the back of the board and are generally more active in endgames. The knights and central pawns have the lowest survival rates. Many popular openings involve d and epawns undertaking suicide missions, which are sometimes counter-attacked with cpawns. The wing pawns have a higher survival rate, prompting one forum user to comment …, “If you can’t be the king, be the little…