Up until 954.7 generations ago, the count of W deme was 6769. Following that period, it changed to 4291, where it has persisted until now.
time_units: generations
demes:
  - name: W
    start_time: .inf
    epochs:
      - start_size: 6769
        end_time: 954.7
      - start_size: 4291
        end_time: 0