Why does Diet Coke go higher than Sprite?

there is more coarbon dioxide in Diet Coke than in Sprite

as the carbonation process of diet coke in in much higher quantities the CO2 in the bottle of diet coike is much higher than in sprite

eg the amount of co2 given off in 330 ml of coca cola is 660 cm3 where as the amount given off from a sprite can is 400cm3

get it?