[Feature request] Average option for bar chart

[paulosouzafmt]

[Suggestion] When there is more than one value for each x-axis item, the sum occurs, you could add a choice option for it to occur in relation to the mean.

Leave an example:
x y
1 15
1 20
1 20
2 20
2 20
3 15
3 30
3 45

In this case for x =1 the y is 55 (sum), it would be interesting if there was the option to average Y in relation to X.