Once a stronghold of the middle class, labor unions have seen a steady decline in membership, particularly in the private sector — including in the construction industry.According to the U.S. Bureau of Labor Statistics, total union membership in 2015 was approximately 40 percent less than what it was in 1983, and the percentage of construction workers who are union members dropped 4 percent to 13.2 percent between 2002 and 2015.Why have unions seen a downturn in recent years? And what factors should commercial plumbing contractors consider when deciding between union and nonunion labor?LOOKING AT THE EXPENSEThe primary impetus behind this
