Economic growth has been exceptionally robust in the United States this year, with GDP forecast to rise by 5¼ per cent. This would be the fastest rate of growth since 1984. The acceleration in the growth rate this year is particularly unusual given the duration of the present economic expansion. Although there remain few signs of an abrupt slowdown, the present situation cannot be sustained indefinitely since the growth rate of aggregate demand is well above that of potential supply, even allowing for some improvement in the underlying rate of productivity growth.