For deme X, the population count was 7045 until a change 6230.7723 generations ago, where it reduced to 3682, remaining steady thereafter.
time_units: generations
demes:
  - name: X
    start_time: .inf
    epochs:
      - start_size: 7045
        end_time: 6230.7723
      - start_size: 3682
        end_time: 0