The 1990s was a decade labor union bosses would rather forget. Although unions registered a slight increase in members in 1998 and 1999, over the decade more and more American workers said no thanks to organizing efforts.

So in order to remain viable, unions are pursuing mergers. For smaller unions, mergers provide access to much-needed financial and organizational resources. Experts say that unions with less than 500,000 members lack sufficient resources to grow. For larger unions, absorbing their smaller counterparts offers a way to add tens of thousands of new dues-paying members without having to mount an expensive and time-consuming organizing drive.

• At least 39 union mergers have taken place since 1990.

• That's up from 35 in the 1980s, 27 in the 1970s and 24 in the 1960s.

• The pace of merger activity has slowed slightly recently, but that largely reflects the fact that there are fewer unions left.

• When the American Federation of Labor merged with the Congress of Industrial Organizations in 1955, the newly-formed AFL-CIO had more than 150 affiliated unions compared to just 68 now.

Moreover, that number will further decline in coming months as proposed mergers are finalized.

Unions once embraced more than one-third of all American workers. But now they represent only 13.9 percent of the total workforce.

Source: Yochi J. Dreazen, "Labor Unions Turn to Mergers in Pursuit of Growth," Wall Street Journal, September 1, 2000.