Deme Y maintained a population of 2817 until there was a shift 5625.265 generations ago that grew its numbers to 8535, a figure that has remained the same since.
time_units: generations
demes:
  - name: Y
    start_time: .inf
    epochs:
      - start_size: 2817
        end_time: 5625.265
      - start_size: 8535
        end_time: 0