The Times has converted all of its 1964 issues into a digitized, searchable format. Each week, The Upshot will unearth an item from 50 years ago and put it in the light of today. “U.S. Finds Unions Gaining Members, Reversing Trend” appeared on May 25, 1964, and can be seen in its original format on TimesMachine.

A government report issued in 1964 found that union membership in the United States had recently broken a five-year decline, rising to almost 16.6 million workers, or 23.5 percent of the civilian labor force. It attributed the turnaround to growth in union membership in the public sector, particularly in the federal government, where President John F. Kennedy had given employees the right to unionize in 1962.
http://www.nytimes.com/2014/05/30/up...970s.html?_r=1