The number of individuals in deme Z remained at 8459 until 1560.0 generations ago, at which time it increased to a new stable size of 8522.
time_units: generations
demes:
  - name: Z
    start_time: .inf
    epochs:
      - start_size: 8459
        end_time: 1560.0
      - start_size: 8522
        end_time: 0