Sharona just got a new hot tub whose heating system operates as a heat pump. The company who sold her the hot tub claimed that the heating system would save her a lot of money on energy bills due to the heat pump's high efficiency.

On a fairly cold day when the air outside the hot tub is 55F, she decides to heat the water in the hot tub to

100F, which is a pretty standard temperature. Once the hot tub has gotten the water to the target temperature and is maintaining that temperature, its heating system needs to extract thermal energy from the air at a rate of 1.3kW while it consumes electrical energy at a rate of 589W. At what percent of its theoretical maximum coefficient of performance is the hot tub heating system operating?