Deme D had an initial size of 614 until 4511.2 generations ago. At that time, its population size changed to 3567, and has remained there till current time.
time_units: generations
demes:
  - name: D
    start_time: .inf
    epochs:
      - start_size: 614
        end_time: 4511.2
      - start_size: 3567
        end_time: 0