It is hard to compare precisely the compensation of union and nonunion workers because individual workers differ by age, length of time on the job and other characteristics. By comparing the wages of workers within occupational categories, the union difference becomes clearer.

Union membership brings one of the greatest pay differences in the protective services, where members earn $737 per week, compared with $477 for nonunion workers—a difference of 55 percent. The union difference means that union machine operators earn 45 percent more than nonunion workers, and union administrative and clerical workers earn 34 percent more than employees who don't belong to unions. In 1999, nonunion salespeople were reported by the Department of Labor as earning slightly more than union workers.

OCCUPATION	UNION	NON-UNION	% DIFFERENCE
Total	$672	$516	30
Exec., Administrative, Mgr.	$823	$789	4
Professional	$826	$794	4
Technicians	$714	$608	17
Sales	$513	$523	-2
Administrative-Clerical	$574	$429	34
Service, Protective	$737	$477	55
Service, Other	$412	$303	36
Precision, Craft, Repair	$755	$546	38
Machine Operators	$572	$394	45
Transportation, Moving	$668	$478	40
Handlers, Laborers	$507	$340	49
Farm, Forestry, Fish	$512	$322	59