Perhaps no nation expends more effort toward measuring its economy than the United States. GDP, consumer prices, industrial production, housing starts, corporate earnings, retail sales, job creation...the financial world receives a continuing stream of information that helps Wall Street set the price for various asset classes, the chief among these being stocks and bonds.
Moreover, most of the key statistics are widely-known, long-standing indicators of economic activity. Others, however, are lesser-known -- but often equally telling -- barometers of the nation's health. One of those involves unemployed workers.
The 13% threshold
The U.S. Labor Department announced that in December 2007, 7.66 million adults were unemployed, a 13.2% increase from December 2006, when 6.70 million adults were out of work.
The significance? In nine previous economic cycles since 1950 with a 13% rise, the annual rise in unemployed adults has signaled a recession every time, The New York Times reported.
With Wall Street still digesting the latest round of sub-par economic data even as it braces for potentially more, economists and analysts said investors can look forward to one 'certainty' in the weeks ahead -- market volatility, as the financial community gauges the U.S economy's probable economic path for 2008. 
Siemens (SI): More than layoffs, a strong sign of recession
McDonald's continues its coffee crusade
Cramer on BloggingStocks: Paulson and Bernanke step up to the plate
