For input power from wall, you would not be far off to take odometer reading (in miles) and divide by 3.5. This will give approximate kWh used (assuming all charging has been at L2 6 kW rate). Divide miles by 4.0 if charging at 3.3 kW L2 rate.
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015