For deme Z, the population count was 1014 until a change 8436.94 generations ago, where it increased to 1862, remaining steady thereafter.
time_units: generations
demes:
  - name: Z
    start_time: .inf
    epochs:
      - start_size: 1014
        end_time: 8436.94
      - start_size: 1862
        end_time: 0