How should I calculate an efficiency of a regulator?

LDO Linear Regulators

The self-power consumption is given by follow formula.

Some type of product is increased a self-current consumption I_Q with the increase of the output current. Therefore, a self-current consumption should confirm increasing ground current from electrical characteristics on data sheet.
However the self-current consumption of NJM7800 series are not increased with increasing of the output current.

The following explanation is based on an example with NJM2884-03.
The circuit diagram of NJM2884-03 is shown at Fig1.
Vin=4V Vo=3V Io=300mA I_Q=5mA (a quiescent current at output current 300mA)

The ground current vs. output current of NJM2884-03 shown at Fig2.
The ground current means the quiescent current in case of flowing the output current.

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  Fig1:Circuit Diagram

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  Fig2:Ground Pin Current VS. Output Current