The population of deme F held at 9409 until 4768.0 generations back, when it reduced reaching 6790, which has been constant since then.
time_units: generations
demes:
  - name: F
    start_time: .inf
    epochs:
      - start_size: 9409
        end_time: 4768.0
      - start_size: 6790
        end_time: 0