- The Employment Situation Summary is released on the first Friday of every month at 8:30 a.m. Eastern time. At 8 sharp, a group of reporters is locked in a room with a press officer from the Bureau of Labor Statistics and allowed to see the top-secret employment numbers. At 8:29:50, eyeing a clock synchronized to official U.S. Naval Observatory time, the press officer starts counting down the seconds and then announces, “Transmit!” freeing the reporters to spread the news. The roughly 30-page report is simultaneously dispatched to nearly 14,000 email subscribers.

- To be considered unemployed, a person must be at least 16, available for work, and actively seeking a job. In the first six months of 2007, the average number of unemployed Americans hovered around 6.9 million, an unemployment rate of about 4.5 percent. During the past decade, the average U.S. unemployment rate was 4.93 percent. North Dakota had the lowest average rate, with 3.2 percent, while the District of Columbia had the highest, with 6.85 percent.

- The first major effort to count out-of-work Americans began during the Great Depression. The government wanted to help the unemployed but didn’t know how many there were. In 1937, President Franklin Roosevelt dispatched “report cards” with questions about job status to every residential mailbox in the U.S. In March 1940, the Work Projects Administration produced the forerunner of today’s monthly report. The tally: 9.1 million unemployed, or a 16.4 percent unemployment rate.

- The report is based on the Current Population Survey, for which the Census Bureau and the B.L.S. conduct monthly interviews of approximately 55,000 households. Initial interviews take place in person and last about 20 minutes. As recently as 1993, the first question depended on whether the respondent appeared to be a “homemaker,” so men and women were asked different things.

- Because the unemployment rate is based on a relatively small sample of the population, it has a significant margin of error. For any given month, the number needs to move by more than 0.2 percentage points for statisticians to be sure that it even moved at all. In 2006, that occurred only three times.

- Counting the unemployed employs roughly 2,000 people, all of whom work for the Census Bureau. A small percentage are based at call centers in Tucson; Hagerstown, ­Maryland; and Jeffersonville, Indiana. The rest conduct in-person interviews in the field. Last year, the B.L.S. spent $40 million conducting the survey.