The economy grew at a slightly slower pace last year than previously believed, but posted the fastest annual growth rate in almost four years and the strongest among industrialized nations, according to government data released Friday.

Gross Domestic Product expanded by an annual rate of 4.1 percent as Americans bought more cars and foreign sales of oil and soybeans, which now face Chinese tariffs, gave exports their biggest boost in more than four years.

The Commerce Department reports that the gross domestic product, the country's total output of goods and services, posted its best showing since a 4.9 percent gain in the third quarter of 2014.

The government each year revises the GDP figures back for three years. But every five years, it conducts a "comprehensive update," which examines GDP figures back to 1929.

The biggest change in the new report is that proprietors' income, the earnings reported to the Internal Revenue Service by proprietors and partnerships, was under-reported.

The overall GDP growth rate last year stands at 2.2 percent, down from 2.3 percent previously reported.