11  There is no necessary reason, of course, why such trade need be imbalanced. deficits and accumulated debt that is arguably more secular than cyclical. The secular updrift in deficits and debt doubtless has been gradual.
However, the component of those broad measures that captures the share of net foreign financing of the balances of individual unconsolidated U.S. economic entities--our current account deficit--has increased from negligible in the early 1990s to more than 6 percent of our GDP today. The acceleration of U.S. productivity, which dates from the mid-1990s, was an important factor in this process.