Below is an instruction from Human. Write a response.
    ### Instruction:
    How many people are affected by lactose intolerance ?
    ### Response:
    Lactose intolerance in infancy resulting from congenital lactase deficiency is a rare disorder. Its incidence is unknown. This condition is most common in Finland, where it affects an estimated 1 in 60,000 newborns.  Approximately 65 percent of the human population has a reduced ability to digest lactose after infancy.
    