Z deme's population was steady at 2913 before it decreased to 1234 5357.296 generations ago, maintaining that number to the present.
time_units: generations
demes:
  - name: Z
    start_time: .inf
    epochs:
      - start_size: 2913
        end_time: 5357.296
      - start_size: 1234
        end_time: 0