The number of individuals in deme D remained at 939 until 3290.45 generations ago, at which time it increased to a new stable size of 6629.
time_units: generations
demes:
  - name: D
    start_time: .inf
    epochs:
      - start_size: 939
        end_time: 3290.45
      - start_size: 6629
        end_time: 0