Until 4694.6 generations ago, the population of deme Z was 3187. At that point, it grew to 9731, where it has stayed up to now.
time_units: generations
demes:
  - name: Z
    start_time: .inf
    epochs:
      - start_size: 3187
        end_time: 4694.6
      - start_size: 9731
        end_time: 0