W deme's population was steady at 4323 before it changed to 7620 9576.0107 generations ago, maintaining that number to the present.
time_units: generations
demes:
  - name: W
    start_time: .inf
    epochs:
      - start_size: 4323
        end_time: 9576.0107
      - start_size: 7620
        end_time: 0