W deme's population was steady at 6637 before it reduced to 1051 1929.0 generations ago, maintaining that number to the present.
time_units: generations
demes:
  - name: W
    start_time: .inf
    epochs:
      - start_size: 6637
        end_time: 1929.0
      - start_size: 1051
        end_time: 0