field AVERAGE value

[tempo]

is it possible to calculate the AVERAGE value of a custom field using XThreads?

i'm looking to create a site (based on myBB) about car's fuel consumption. Any user must input data about fuel consumption (like km or miles, the price of the refuel, the driving conditions etc). So the site calculates the car's consumption and helps to manage the vehicle's costs.

Do you have a plan about this?
Is it possible to do this using XThreads or it isn't?

thanks for the support