Non-Union Businesses Grow Faster

What Happened to American Unions?
02/12/09 - Econlog.Econlib.org by Bryan Caplan From Brink Lindsey's "Nostalgianomics":

[edited] Henry Farber of Princeton and sociologist Bruce Western of Harvard report that the main cause of declining union membership as a fraction of all workers, has been the slower growth of unionized workplaces compared to nonunionized.

Between 1973 and 1998, employment at
- nonunion companies grew at 2.8% a year
- unionized companies declined at 2.9% a year

Keeping up unions membership would have required organizing new workers at the rates of the early-1950s. But, organizing rates have declined steadily since then. Percent union membership has declined steadily since the 1970's.