Robotics systems are thus becoming an economically viable alternative to human labor in more and more industries. A human welder today earns around $25 per hour (including benefits), while the equivalent operating cost per hour for a robot is around $8 when installation, maintenance, and the operating costs of all hardware, software, and peripherals are amortized over a five-year depreciation period. In 15 years, that gap will widen even more dramatically. The operating cost per hour for a robot doing similar welding tasks could plunge to as little as $2 when improvements in its performance are factored in.
Emphasis added by me.