(Washington, DC) -- The Securities and Exchange Commission is proposing a new rule that would require corporations to disclose how much their CEOs get paid compared to one of their workers.

Unions are behind the rule. The president of the AFL-CIO said big disparities between CEO and worker pay affects company performance, and that information should be shared with investors. Business groups aren't too fond of the measure.

A recent report indicated that the pay gap between CEOs and average workers grew from nearly 200 to one in 1993 to around 350 to one last year.

The SEC voted to propose the rule by a vote of three to two. There will be a 60-day period for public comment.