Initially, the population size of deme Y stood at 2819, but this changed 4362.2936 generations ago when it changed to 8213, and it has been stable at that size up to today.
time_units: generations
demes:
  - name: Y
    start_time: .inf
    epochs:
      - start_size: 2819
        end_time: 4362.2936
      - start_size: 8213
        end_time: 0