All that U.S. shale oil has significantly improved the U.S. trade picture.

The nation’s trade deficit ballooned to nearly $70 billion a month in 2006, but the gap has remained considerably lower since then thanks in no small part to soaring production of domestic petroleum.

In June, the difference between how much petroleum the U.S. imports and exports in dollar terms fell to its lowest level in almost four years: $17.4 billion. The gap had leaped to a record $42.4 billion just five years earlier.

The picture looks similarly bright in inflation-adjusted terms. The so-called real oil deficit shrank to $11.4 billion in June vs. a high of $24.1 billion in 2005, using a three-month rolling average.