J deme's population was steady at 9001 before it reduced to 5188 2932.0 generations ago, maintaining that number to the present.
time_units: generations
demes:
  - name: J
    start_time: .inf
    epochs:
      - start_size: 9001
        end_time: 2932.0
      - start_size: 5188
        end_time: 0