American union membership in the private sector has in recent years fallen under 9% — levels not seen since 1932. Workers seem uninterested in joining, and strike activity has almost faded away. The labor force in unionized automobile and steel plants, for example, has fallen dramatically. In another example, Construction trades now only represent approximately 14% of the labor market. The inability to prevent non-union companies from taking significant market share has undercut union membership.
Union labor is not the cause of our economic problems as some would have us believe. Maybe you can throw some of the blame on the unions in the auto industry but there problems started back in the late 40's and early 50's when those crapy imports started to show. Detroit laughed instead of retooling and the imports retooled and now they are laughing.