How to select field from doc type on dashboard

I have created a new doc type. the doc type is power consumption where in I record 4 fields. Now when i try to create a chart using the power consumption doc type with count type of chart, it is not letting me chose which field i want the chart of. How do i do this?

Looks like you need to have numeric fields (currency, int, float etc.) so that charts can be drawn up based on the values. Please verify your custom doctype fields.

Okay i think i found it. I was using count as the type of chart, now i moved to average and i got the right values. Now the problem is having more than 1 data points in a dashboard chart… is it possible?