Last month, more than 4 million American businesses, including 960,000 retailers, were sent 2007 Economic Census forms. The surveys collect data on sales, locations, employees and wages. Businesses that received a form are required by law (Title 13, U.S. Code) to complete and return it by Feb. 12, 2008.

The information is collected every five years, and industry averages are made available at the Web site, http://ask.census.gov . For example, the average 2002 annual wages paid per employee at electronics and appliance stores, $23,861, were higher than the average wages paid at pharmacies and drug stores, $19,758.