But policymakers will need to be on the alert for oil-driven, indeed energy-driven, risks to our expansion. Looking further ahead, some of those favorable factors that I discussed earlier - in particular, growing fiscal surpluses and accelerating productivity - remain in place, but presumably will not persist indefinitely.
The mounting fiscal surpluses have been an important source of national saving, muting upward pressures on interest rates at a time of strong demand for private credit. By keeping the cost of capital lower than it otherwise would have been, the surpluses have contributed to capital deepening and faster growth of productivity.