Until a shift occurred 7135.3 generations ago, deme X's population was consistently 8195. Since then, it changed to 8183, a number that has remained unchanged to the current time.
time_units: generations
demes:
  - name: X
    start_time: .inf
    epochs:
      - start_size: 8195
        end_time: 7135.3
      - start_size: 8183
        end_time: 0