The nation's private company CEOs are growing more pessimistic about the U.S. and world economies, according to Pricewaterhouse Coopers.

Less than 20 percent of 245 CEOs recently polled said they had a positive outlook on the U.S. economy over the next 12 months, down from 64 percent last year and a 16-year low, the New York-based accounting firm reported this week.

Confidence in the world economy also fell sharply. Only 19 percent of CEOs surveyed said they were optimistic about global economic performance in the year ahead, down from 55 percent last year.

Despite the growing pessimism, nearly 40 percent of companies doing business internationally reported increased sales abroad, up by three percent, the survey found. These same companies were also projecting higher revenue growth than those operating solely in the domestic market.

"While their margins remained tighter this quarter and costs increased, international marketers had more price flexibility and the ability to better distribute products across a number of different markets and economies," Ken Esch, a partner with the firm, said in a statement.

The survey also found that bank lending will become increasingly important for all companies in the face of the credit crisis.

"As the economy slows down and customers begin to delay payments, many companies will turn to new bank loans to stabilize cash levels and subsidize slow payments," Esch said.