History of chess
The table, based roughly on square control, suggests the modern game deploys about 20% more force on the board than the older game. However, this understates the case, since the table does not allow for castling, nor the initial optional double move of the pawn. Also, the pawn promotion to the new queen is hugely significant when it takes place. No exact value can be placed on these elements, but perhaps the modern game makes use of up to a third more force than in the original game. Also, the fast development of the pieces makes the opening far more important in the modern game.