The Dow Jones Industrial Average (^DJI 0.57%) is America's most-watched index, and it's given us a lot of insight into the changing American economy over the years. You probably know more about the Dow than you think, simply because it's so closely followed by the financial news media. However, there are many fascinating facts about the Dow that lurk just beneath this day-to-day noise. We learned a few interesting bits of information about the Dow and its 30 representative companies yesterday, and today we're going to dig a little deeper into the details to find out more about the blue-chip index and what it says about the American economy today.

1. The Dow's 30 components together are worth nearly $5 trillion
From the largest market cap (ExxonMobil's (XOM -0.29%) $435 billion) to the smallest (Travelers' (NYSE: TRV) $32 billion), the 30 companies that make up the Dow are worth a combined $4.82 trillion today. To put that in perspective, that much money could pay for:

Source: U.S. Navy artist via Wikipedia.

  • 3,210 Burj Khalifa skyscrapers  (the tallest building in the world)
  • 370 new Ford-class aircraft carriers 
  • 32 International Space Stations 
  • 10 almost-new Interstate Highway Systems 
  • About a quarter of the U.S. national debt 

2. The 30 Dow components make a lot of revenue
Multibillion-dollar market caps almost always mean multibillion-dollar revenue streams, and the Dow's 30 components certainly meet that criteria. The lowest annual revenue reported by any Dow company for the most recent fiscal year was Visa's (V 0.33%) $11.8 billion, which is still larger than the gross domestic products s of 66 countries or territories! The combined annual revenue of all 30 Dow companies is $2.83 trillion as of their most recent budget years, which would earn the Dow fifth place in global GDP if it were an independent country with 30 separate provinces. That's larger than France, Brazil, Italy, Spain, and Mexico combined!

 3. The Dow's components earn a lot of profit, too
Every Dow component is profitable, and their combined net income for the latest fiscal year added up to $325 billion. That's enough to buy all but two Dow companies -- ExxonMobil and Microsoft (NASDAQ: MSFT), which is currently worth several billion dollars more -- outright! Many Dow components also boast huge foreign cash hoards, but this profit stream would still only be enough to account for one-sixth of the $1.95 trillion American companies have now stashed abroad.

4. The Dow's components employ over 6 million people
Only one of the Dow's 30 companies -- Visa again, with a mere 9,500 reported employees -- has fewer than 30,000 people on its payroll, and many employ 75,000 or more. Retail behemoth Wal-Mart (WMT 0.36%) contributes the lion's share of the Dow's employees, as it reported a workforce of 2.2 million in its latest fiscal year. All told, there are 6,523,793 people working for the Dow's 30 components. That's enough people to make the Dow the 17th most-populous state in the U.S., ahead of Tennessee, Minnesota, Colorado, or Kansas.

Source: James Cridland via Flickr.

5. For Dow components, it pays to pump oil, but not to serve customers
The 30 Dow companies' reported revenue and earnings, and their reported employee numbers, give us an easy window into the relative profitability of each company. Of these 30 companies, two of the three most-profitable per employee are Big Oil representatives ExxonMobil and Chevron (NYSE: CVX), and the three least-profitable per employee are all retail outlets -- Wal-Mart earned only $7,575 in profit per employee in its latest fiscal year, but Home Depot (NYSE: HD) and McDonald's (NYSE: MCD) weren't far behind, as they were the only other Dow companies to earn less than $15,000 in profit per employee.

The Dow's most-profitable company, however, was all about moving money -- Visa cleared a whopping $526,316 in profit per employee last year.