What is the volume of an average pond?

At our water garden center, Aquatic Connections, the two most popular pond sizes are 8ftx11ft and 11ftx16ft. If the average depth is 2 feet, that would mean the gallons of water would be roughly 1300-1500 gallons for the 8x11 and 2000-2500 gallons for the 11x16. The difference would depend on the amount of rock in the bottom of the pond.