aggregate_type = avg and time_length = all

[Marc Cauhopé]

Hello, I want to calculate the AVERAGE MONTHLY precipitation of all my readings.
I replaced "max" by "avg" in the example "Grouping rain totals" of Charts documentation.
I get a graph of the cumulative TOTAL but not the average.
Thank you for helping me.

[raintotals]
    title = Rain Totals by Month
    show_button = true
    button_text = Rain Totals
    type = column
    time_length = all
    aggregate_type = avg
    aggregate_interval = 86400 # 1 day

    [[rainmonthtotals]]
        title = Historical Rain Totals By Month
        subtitle = Rain Totals for All Months for All Time
        xAxis_groupby = month
        xAxis_categories = 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
        [[[rainTotal]]]
            name = Rain Total