Deme W maintained a population of 5217 until there was a shift 8185.71 generations ago that changed its numbers to 973, a figure that has remained the same since.
time_units: generations
demes:
  - name: W
    start_time: .inf
    epochs:
      - start_size: 5217
        end_time: 8185.71
      - start_size: 973
        end_time: 0