From Bureau of Labor Statistics
How are seasonal fluctuations taken into account?
Total employment and unemployment are higher in some parts of the year than in others. For example, unemployment is higher in January and February, when it is cold in many parts of the country and work in agriculture, construction, and other seasonal industries is curtailed. Also, both employment and unemployment rise every June, when students enter the labor force in search of summer jobs.
The seasonal fluctuations in the number of employed and unemployed persons reflect not only the normal seasonal weather patterns that tend to be repeated year after year, but also the hiring (and layoff) patterns that accompany regular events such as the winter holiday season and the summer vacation season. These variations make it difficult to tell whether month-to-month changes in employment and unemployment are due to normal seasonal patterns or to changing economic conditions. To deal with such problems, a statistical technique called seasonal adjustment is used. This technique uses the past history of the series to identify the seasonal movements and to calculate the size and direction of these movements. A seasonal adjustment factor is then developed and applied to the estimates to eliminate the effects of regular seasonal fluctuations on the data. When a statistical series has been seasonally adjusted, the normal seasonal fluctuations are smoothed out and data for any month can be more meaningfully compared with data from any other month or with an annual average. Many time series that are based on monthly data are seasonally adjusted.
Series Id: LNU04000000Not Seasonally AdjustedSeries title: (Unadj) Unemployment RateLabor force status: Unemployment rateType of data: PercentAge: 16 years and over
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
1999 4.8 4.7 4.4 4.1 4.0 4.5 4.5 4.2 4.1 3.8 3.8 3.7 4.2
2000 4.5 4.4 4.3 3.7 3.8 4.1 4.2 4.1 3.8 3.6 3.7 3.7 4.0
2001 4.7 4.6 4.5 4.2 4.1 4.7 4.7 4.9 4.7 5.0 5.3 5.4 4.7
2002 6.3 6.1 6.1 5.7 5.5 6.0 5.9 5.7 5.4 5.3 5.6 5.7 5.8
2003 6.5 6.4 6.2 5.8 5.8 6.5 6.3 6.0 5.8 5.6 5.6 5.4 6.0
2004 6.3 6.0 6.0 5.4 5.3 5.8 5.7 5.4 5.1 5.1 5.2 5.1 5.5
2005 5.7 5.8 5.4 4.9 4.9 5.2 5.2 4.9 4.8 4.6 4.8 4.6 5.1
2006 5.1 5.1 4.8 4.5 4.4 4.8 5.0 4.6 4.4 4.1 4.3 4.3 4.6
2007 5.0 4.9 4.5 4.3 4.3 4.7 4.9 4.6 4.5 4.4 4.5 4.8 4.6
2008 5.4 5.2 5.2 4.8 5.2 5.7 6.0 6.1 6.0 6.1 6.5 7.1 5.8
2009 8.5 8.9 9.0 8.6 9.1 9.7
Therefore, in June 2009, the not-seasonally adjusted unemployment rate was 9.7%, versus 9.5% seasonally adjusted.
I'd say that when the rate gets to this level a lot of people just give up and are not counted. It's probably well over 10.0% - there are probably millions that have not been in the workforce for years that would like to work now due to a family situation....but there are no jobs.