Nowhere near that close, actually. Closer to 33% and that is before the inevitable financial incentives provided by the engine OEM to secure the airline's selection (which can be up to 75% of the value of the engines). For sole source engine aircraft (737MAX, 777-300ER, etc.) the incentives are still there, but are typically controlled by the airframe OEM to dish out as discounts on the price of the aircraft.

Having now worked on both the engine and airframe side of the business, I can say with confidence that the engine side is, by far, more complex (and interesting) from a business perspective.