Deme Y had an initial size of 8667 until 4202.0 generations ago. At that time, its population size reduced to 7966, and has remained there till current time.
time_units: generations
demes:
  - name: Y
    start_time: .inf
    epochs:
      - start_size: 8667
        end_time: 4202.0
      - start_size: 7966
        end_time: 0