there normaly between 1-16 bottom levels, and you can get a ton. just have to devote your self to looking for them, lets face it minecraft is a limitless world of discovery. so you could find any possible amount. curently ive found over 200, but ive also spend like 5 or more hours a day playing and i mine just about the whole time... if your person could get a tan in the game mine would be pure white and resemble one of those fish at the very bottom of the sea. lol i see the sun only for supplies and thats only it its sunny when i come back up for stuff.
What's The Most Amount Of Diamonds You've Ever Found?