Since its inception in 1985, American Lawyer’s Am Law 100 rankings of the nation’s 100 top-grossing law firms have been dominated by three firms: Baker & McKenzie, DLA Piper and Skadden, Arps, Slate, Meagher & Flom. But in the 2015 rankings, released Monday and available at www.americanlawyer.com, DLA Piper has been displaced. The new kid on the block: Los Angeles-based Latham & Watkins, thanks to an increase in revenue of more than 14 percent, to $2.6 billion, the most revenue ever accrued by a single Am Law 100 law firm. Average revenue per lawyer at the 100 top-grossing firms? $871,958, up 3.7 percent.