googleapi面积图的折线图笔划中如何显示点值?

How to display the point value in the line chart stroke of google api area chart?

我需要在面积图中显示点值。我在折线图中找到了如何做,但在面积图中找不到。有人能给我指出正确的方向吗?

注释列应该跟在每个应该显示的系列列之后,
如下...

["Month", "2018", {type: "string", role: "annotation"}, "2019", {type: "string", role: "annotation"}, "2020", {type: "string', role: "annotation"}],
["Jan", 30.4, "30.4", 24.9, "24.9", 26, "26"],