FORTUNE -- The numbers are in, and America isn't quite the corporate leader it has been in the past. While the U.S. still has more companies than any other country on the Fortune Global 500 list (133), that number has dropped significantly since 2005, when 176 of the world's biggest companies had headquarters in the States.
A couple of shifts in this year's Global 500 list reflect key business trends: Emerging markets continue to emerge, Big Oil is becoming an increasingly global phenomenon, and the economic crisis has muddied the distinction between private business and government.
Japan's earthquake and tsunami certainly took a toll on its economy, which was on a downward slide long before the quake. In 2005, Japan had 81 companies on the Global Fortune 500 list. This year, the country claimed 68. Also, four Japanese companies made the top 25 six years ago. In 2011, Toyota (TM) is the only classic Japanese company left standing. The other, Japan Post Holdings, is an offshoot of the Japanese postal service, which the government attempted to privatize in 2005 to boost a national economy that is still in need of such a boost.
Energy is king
The energy industry continues to enjoy a strong representation among the world's largest corporations. In 2005, six out of the top 25 biggest companies in the Global Fortune 500 were in the petroleum refining industry. The industry has only grown in stature: nine out of the top 25 on the 2011 list are in the energy sector.
See the full list: The World's Largest Companies
BRIC by BRIC
The growing force of the global energy industry is certainly prevalent in Brazil, Russia, India, and China, all of which are moving up on the Global 500 list. Russia and Brazil claimed three companies on the list in 2005, and both have seven this year. China, which had 16 companies on the list in 2005, now has a whopping 61.
The largest companies represented by every single BRIC country are in the energy industry, and all of these companies have grown in global stature through the years.
Brazil's Petrobras ranked number 125 in 2005; this year, it's up to 34. Similarly, Indian Oil rocketed from 170 to 98 within the same amount of time. Gazprom, Russia's gas-heavy energy provider is currently sits in the no. 35 spot, up from 139 in 2005. China's Sinopec was a major player even in 2005 -- ranked at 31 -- and this year, it is ranked as the fifth largest company in the world.
The patriotic enterprise
Many of the largest companies outside the U.S., especially those based in emerging markets, are connected to their national governments. But the U.S. is no longer as distinct as their global counterparts on that front: three of America's biggest companies -- Fannie Mae (no. 15), GM (GM, Fortune 500) (no. 20) and Bank of America (BAC, Fortune 500) (no. 21) -- maintain strong financial ties to the U.S. government. 
