In January 2008, within the private sector, workers in manufacturing had the highest median tenure with their current employer among the major industries (5.9 years). This is according to data released by the U.S. Department of Labor's Bureau of Labor Statistics.
In contrast, workers in leisure and hospitality had the lowest median tenure (2.1 years).
These differences in tenure reflect many factors, one of which is varying age distributions across industries. Workers in manufacturing tend to be older on average than workers in leisure and hospitality.
This data is from the Current Population Survey. To learn more, see "Employee Tenure in 2008," (PDF) (HTML) news release USDL 08-1344.