It is pretty rare so I am going to say 1 out of 1000. Keep doing those 12 ounce arm curls!
A handicap (or "odds") in chess is a way to enable a weaker player to have a chance of winning against a stronger one. There are a variety of such handicaps, such as material odds (the stronger player surrenders a certain piece or pieces), extra moves (the weaker player has an agreed number of moves at the beginning of the game), extra time on the chess clock, and special conditions (such as requiring the odds-giver to deliver checkmate with a specified piece or pawn). Various permutations of these, such as "pawn and two moves", are also possible.
Handicaps were quite popular in the 18th and 19th centuries, when chess was often played for money stakes, in order to induce weaker players to play for wagers. Today, except for time odds, handicaps are rarely seen. Rybka, however, a top-rated computer chess engine, played a successful series of handicap matches in 2007 and 2008 against human chess masters. Environment