It ensures that all values are visible, and no data set is hidden by others. However, the y-values no longer represent absolute values, except for the last column which is drawn at the bottom of the stacked areas.
堆叠 - 此子类型绘制彼此堆叠的累计值。保证所有值都可见，并且没有数据集被其他所隐藏。但是，y 值不再表示绝对值，除非被绘制于堆叠区域底部的最后一列。