NEW YORK (CNNMoney) - The United States government has a black chief executive. But 99% of the nation's largest businesses do not.
When Don Thompson assumes his new title as CEO of McDonald's (, Fortune 500) on July 1, a promotion announced Thursday, he will be only the sixth active African-American CEO at a Fortune 500 company.
Thompson, who is currently No. 2 at the fast-food chain, will join Kenneth Frazier of Merck (, Fortune 500), Kenneth Chenault of American Express (, Fortune 500), Ursula Burns of Xerox (, Fortune 500), Clarence Otis of Darden Restaurants (, , who heads privately held TIAA-CREF, as the African-Americans in the nation's top 500 corner offices.
The first African American to head a Fortune 500 company was Franklin Raines, who led mortgage finance firm Fannie Mae from 1999 to 2004. Counting former CEOs at Fortune 500 firms brings the number of blacks who have held that post to only 13, including Thompson.
The list of black executives at the next two levels of the corporate ladder is a little longer, but not much.
Arnold Donald, CEO of the Executive Leadership Council, a professional network of African-American leaders at major U.S. companies, said his group estimates there are fewer than 800 black executives in the top echelons of Fortune 500 firms.
But since those companies have an average of 70 executives at that level, black executives at that level represent only 2% of the potential jobs.
Another public interest group, the Alliance for Board Diversity, found that collectively, women and minorities lost ground in America's corporate boardrooms between 2004 and 2010.
Donald said his group is in the process of launching an outreach program to urge companies to do more for diversity among the top executive ranks, seeking to get each company to add one black executive in the top two levels of the company below CEO over the course of the next five years.
"For companies to be successful, innovation is required, and to have innovation is to have diversity of thinking, " he said. "It's not just African American - you need Hispanics, you need women. But if you have a diversity of people, you have a much better chance of innovating."
Donald said he doesn't believe that it's overt discrimination keeping blacks out of the upper echelons of corporate America.
"Your natural instinct is to cluster with those more like yourself. It's not willful intent to keep someone out, " he said. "Whatever you call it - the good-old-boy network, whatever, it's just human behavior and diversity requires pro-active intervention. It's not a natural thing yet."