New York-based law firms on average grew their profits per equity partner by 9.5 percent last year, far outpacing the industry average, according to a Citi Private Bank annual survey that credited a mix of moderate revenue growth, fewer equity partners and a tight control of costs for the rise.

“It’s fair to say strong expense control has helped New York firms because the revenue growth was decent but, if not for a very disciplined focus on expenses, you wouldn’t have quite the increase on the profits side,” said Dan DiPietro, chairman of Citi Private Bank’s law firm group.