Originally, deme Z had a population size of 6772, which grew to 7749 around 509.687 generations ago and has not changed since.
time_units: generations
demes:
  - name: Z
    start_time: .inf
    epochs:
      - start_size: 6772
        end_time: 509.687
      - start_size: 7749
        end_time: 0