Originally, deme G had a population size of 5004, which decreased to 2020 around 9823.88 generations ago and has not changed since.
time_units: generations
demes:
  - name: G
    start_time: .inf
    epochs:
      - start_size: 5004
        end_time: 9823.88
      - start_size: 2020
        end_time: 0