Whether population swings are short and narrow or long and wide, the average level of world population after several cycles will probably have either an upward or a downward trend overall.

• 不管人口的涨落是短期、小范围的或是长期、大范围的，世界人口的平均水平在经过了几个周期之后，总体上会形成一种或上升、或下降的趋势。