The book The Real Mad Men: The Renegades of Madison Avenue and the Golden Age of Advertising by Andrew Cracknell starts out with a stunner of a claim.
That would be absolutely incredible if true. (And redundant, but it’s early in the book. Like page one of the first chapter early.) Personally, I don’t believe it for a second. (There are no footnotes and a short general bibliography.) New York had tens of millions of square feet of office space from the building spree that lasted throughout the 20s and into the Hoover 30s. Rockefeller Center, the one really big project that came later, added 8 million square feet all on its own. If the 50s doubled the office space just in New York I’d be amazed. The rest of the world combined? Sell me the Brooklyn Bridge while you’re at it.
But I can’t find any hard numbers for earlier time periods. Wiki gives 353 million sq. ft. of office space in 2001 for Manhattan, so that’s a maximum of some sort.
Does anybody want to put their mad search skillz to a test?