Under the constant-money-growth-rate rule, the annual money supply will be constant at the average annual growth rate of:.

real GDP

Explanation:

The above rule was proposed by Milton Friedman that the money supplied by the central bank be increased by constant percentage on annual basis. In other words, constant money growth rate rule suggested money supply growth rate be equal to GDP growth rate annually.

According to Friedman, monetary policy contributes to fluctuation in an economy. He suggested that the best way to stabilize a fluctuating economy is to allow the central bank increase money supply in the long run by a targeted amount annually irrespective of the situation of the economy.