Originally, deme W had a population size of 7749, which changed to 7543 around 8185.0 generations ago and has not changed since.
time_units: generations
demes:
  - name: W
    start_time: .inf
    epochs:
      - start_size: 7749
        end_time: 8185.0
      - start_size: 7543
        end_time: 0