As the U.S. economy continued its steep fall into a deeper recession, many major oil companies – in particular Exxon Mobil – enjoyed a steep ascent into record-setting profits.

The U.S. gross domestic product (GDP), which measures economic activity, fell at a yearly rate of 3.8% in the fourth quarter of 2008 (adjusted for inflation).

That’s the largest drop in GDP since the first quarter of 1982.

Meanwhile, Exxon Mobil posted the largest annual profit of any company in U.S. history on Friday, beating its own 2007 record.

Exxon, the world’s largest publicly traded oil company, recorded $45.22 billion in annual profits in 2008, as oil prices soared. In 2007, the company posted annual profits of $40.61 billion.

Elsewhere the ecomomic slowdown is affecting multiple sectors of the U.S. economoy. Consumer spending, which accounts for more than two-thirds of the nation’s overall economic activity, fell at a 3.5% annual rate, CNN reported.

A key indicator of busniess spending – investment in equipment and software -plummeted, falling at an annual rate of 28%. U.S. exports fell at a roughly 20% yearly rate, according to CNN.

In December 2008, the unemployment rate jumped to 7.2% with 11.1 million jobless people, according to the Bureau of Labor Statistics.

Since the start of the recession in December 2007, the number of unemployed people has grown by 3.6 million and the unemployment rate has risen by 2.3 percentage points, the Bureau reported.

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For Exxon, the picture isn’t all rosy. Its 2008 fourth quarter profit declined 33% amid the drop in crude prices, according to CNN.

Crude prices hit a record $147.27 in July but fell to around $30 in December, which contributed to the massive decline in Exxon’s fourth quarter earnings.

Still, Exxon is faring quite well, despite the fourth quarter declines. Its share prices are only down 9% in the past 6 months, CNN reported. Compare that to the 30-plus-percent drop in the S&P 500.

”ExxonMobil’s financial strength continued to support its disciplined capital investment approach in the midst of a growing global economic slowdown,” Exxon CEO Rex Tillerson said in a statement.

Exxon is not alone among oil companies with its record-setting profits. Royal Dutch Shell reaped the benefits of record crude oil prices, posting full-year profits of $31.4 billion, a record for a European oil company, according to Reuters. In 2007, the company posted a $27.6 billion profit.