The U.S. Treasury’s import duty revenues climbed 92.9% year over year in December to reach $5.99 billion. That was the result of increased duties on steel and aluminum as well as an average 12.3% rate on imports from China. The increase in duties, worth $2.89 billion year over year for the month and effectively a tax on U.S. buyers, comes on top of a $2.53 billion loss of net exports to China in November. The income from tariffs will likely fall going forward as imports decline. New data from the Chinese government shows exports to the U.S. likely fell 9.2% in January from December.