Up until 775.0 generations ago, the count of U deme was 7470. Following that period, it reduced to 5960, where it has persisted until now.
time_units: generations
demes:
  - name: U
    start_time: .inf
    epochs:
      - start_size: 7470
        end_time: 775.0
      - start_size: 5960
        end_time: 0