The U.S. current account deficit unexpectedly fell in the fourth quarter, hitting its lowest level in more than a year, as an increase in the primary income surplus offset a soybean-driven drop in exports.

The Commerce Department said on Tuesday the current account deficit, which measures the flow of goods, services and investments into and out of the country, fell 3.1 percent to $112.4 billion, the lowest since the second quarter of 2015.

The current account deficit for the third quarter was revised up to $116.0 billion from the previously reported $113.0 billion. Economists polled by Reuters had forecast the deficit rising to $128.2 billion in the fourth quarter.

The fourth-quarter current account deficit represented 2.4 percent of gross domestic product, down from 2.5 percent in the third quarter. For all of 2016 the current account deficit totaled $481.2 billion, a 3.9 percent increase from 2015.

That represented 2.6 percent of GDP, unchanged from 2015. The current account deficit has dropped from a record high of 6.3 percent of GDP in the fourth quarter of 2005 as rising domestic oil production and lower global oil prices curbed the import bill.

Goods exports fell $3.4 billion to $371.7 billion in the fourth quarter. That reflected an $8.4 billion decrease in the export of food, mainly soybeans. Exports were also crimped by the dollar, which gained more than 5 percent against the currencies of the United States' main trading partners in the fourth quarter.

The surplus on primary income - which includes investment income such as dividends, and employee compensation - increased $19.9 billion. Primary income receipts increased $4.4 billion to $207.9 billion, reflecting increases in direct investment income, mostly equity and portfolio inflows.

The deficit on secondary income, U.S. government grants, pensions, fines and penalties, and worker remittances rose to $41.5 billion from $41.4 billion in the third quarter.