In a particular coal-fired steam turbine power station, the boiler that burns the coal to produce steam is 77.3% efficient, the turbine that turns the power in the steam into rotational mechanical power is 33.1% efficient and the generator that turns the rotational mechanical power into electrical is 94.0% efficient., what is the overall efficiency of converting coal to electricity in this power station? Give your answer as a percentage (without the % sign) and to one decimal place.