In the more familiar unit of "swimming pools", it looks like it might be around 10.
Olympic sized pool = 164ft x 82ft x 9ft 10 inches = 132, 300ft^3. Density of lead: 709 lbs per ft^3.
So a single Olympic-sized pool would weight almost 94,000,000 lbs if filled with lead.
(If you really want to blow your mind, that same pool would weight almost 200 million lbs if filled with Osmium, the most dense element. Of course, that's WAY WAY more than the amount of Osmium that exists...I can't find a world wide figure but US production is only about 250 lbs per year)