Which of the following is most likely to be the reason behind the decline in the U.S. share of world output in 2014?

• faster economic growth of developing economies, particularly in Asia

• rise in the share of FDI stock accounted for by the U S economy

• increasing share of world output accounted for by other developed nations

• rising barriers to the free flow of goods, services, and capital throughout the globe

• absolute decline in the health of the U.S. economy