In the last three winters, he said, daily exports of crude have dropped by about 130,000 barrels a day.
But exports dropped a little in the last two years to satisfy growing domestic demand.
But imports fell 2.5 percent as exports dropped 1.8 percent.
From 1984 to 1988, exports dropped to almost nothing.
In 1970 they were provided protection and the export of their hides dropped.
In 2010, American exports to Iran dropped by 50% to $281.8 million.
Although exports to Asia dropped 11.4 percent in 1998, he said, the previous year, they rose 14 percent.
But by the 1980's, coffee tea and other exports dropped in price.
Before the 2002 farm bill, American agricultural exports had dropped for five consecutive years.
That is because exports have dropped and the harvest has been good.