Up until 7893.757 generations ago, the count of X deme was 4897. Following that period, it decreased to 4551, where it has persisted until now.
time_units: generations
demes:
  - name: X
    start_time: .inf
    epochs:
      - start_size: 4897
        end_time: 7893.757
      - start_size: 4551
        end_time: 0