NEW YORK (CNN/Money) - U.S. workers at the bottom of the pay scale have seen their chances of being laid off jump in the last two years, while those at the top of the scale have seen their chances dwindle, according to a survey released Tuesday.

Chances of being laid off for employees making less than $50,000 per year soared 43 percent since 2000 and the odds of job loss for those making more than $85,000 per year dropped by 23 percent, outplacement firm Challenger, Gray & Christmas reported.

The trend for lower salaried employees as job cut targets has continued throughout 2002. The percentage of laid off workers making less than $50,000 in their last jobs increased to 27 percent in the first two quarters of 2002 from 18.9 percent in the first two quarters of 2001, the survey found.

Meanwhile, discharged workers earning more than $85,000 in their last jobs fell to 34.5 percent from 45 percent in the same period.

"Even when the economy is fully recovered and companies are back in expansion mode, we may not see a revival in hiring of the rank-and-file worker," said John Challenger, CEO of Challenger, Gray & Christmas. "Cost containment oriented companies, in an effort to become more agile in this increasingly competitive global marketplace, will rely more an more on a just-in-time workforce of contract and contingent workers."

Indeed the current market for contract employees has grown to about $400 billion from about $150 billion in 1998, the firm reported, citing the Outsourcing Institute.

"[Higher paid employees] represent the core of the institution. They have the best understanding of the company's history, its goals and its culture," Challenger added. "They are there to guide the company and its employees. Companies generally have a greater amount of time and money invested in these workers."