EXAMPLE: WILL SLOWED GROWTH OF POTENTIAL U.S. REAL GDP FUEL INFLATION? Economists measure the growth of potential real GDP as a way of determining the rate of which long-run aggregate supply shifts outward. The growth rate was about 3.5 percent in the 1940s and above 4 percent in the 1960s. Between the 1970s and the 1990s, however, the growth rate dropped to around 3 percent. By the early 2010s, potential GDP growth had fallen to a rate of somewhere between 1.0 and 1.5 percent.