NEW YORK (Reuters) - When economists tell us the current U.S. slump could never turn into another Great Depression, they all point to one thing: one of four Americans was out of work in the 1930s.

But since the definition of joblessness has changed over the years, this expert assessment might be too rosy.

As many as 25 percent of Americans were unemployed during the days of bread lines that symbolized the Depression, but that figure is more than three times the current 6.7 percent unemployment rate, the economists say. Even the most pessimistic estimates only foresee the rate rising barely above 10 percent.