Average fixed costs (AFCs) fall as output increases. At first, AFC falls rapidly. For
example, with output doubling from 5 to 10 units, AFC per unit halves. At the higher
levels of output the impact on AFC of an increase in output is less significant. This is
illustrated in the shape of the AFC curve in Figure 5.5b. Although it is continually
downward sloping, its slope becomes increasingly shallow at higher levels of outputs.