Check the five-digit display to see the current, cumulative total kilowatt-hours of electrical consumption, according to PG&E. Take a look at the instructions to see which number reflects the usage, as some smart meters alternate different displays. For example, the Landis+Gyr model uses "88888" to indicate proper function.
Wait until the default code showing operation disappears and the actual usage number comes up. On the Landis+Gyr model, the screen after the "88888" readout shows the cumulative usage. However, on some GE smart meters, the five-digit display showing cumulative use of power is always on and sits on the top line of the readout, unless a segment check is running, in which case the standard display returns shortly, as stated by PG&E.
In some cases, the readout showing proper function doesn't have any numbers. For example, the smart meters used by AEP Texas show the code "OPN" to mean that the power is off and "CLS" to mean that the power is on. This company's smart meters have different reference codes for the different types of information that the meter expresses, notes AEP Texas. The list of reference codes should appear in the documentation that you receive when you sign up for utility services.