(FORTUNE Magazine) – The U.S. has the most companies on the Global 500 list, with 161, up four from last year (six arrived, two dropped off). Japan has 128, followed by Britain, Germany, and France. But 29 other countries are represented, from Argentina (Yacimientos Petroliferos Fiscales, or YPF) to Zambia (Zambia Industrial & Mining). Some small countries have a disproportionately large number of companies on the list: Sweden (pop. 8.6 million) has 14, and Switzerland (pop. 6.8 million) has nine. Four of the 18 newcomers are in Scandinavia, including No. 500, Orkla, a Norwegian food maker with $2.7 billion in annual sales. Argentina has begun privatizing YPF, its state oil company. It started selling shares on the New York Stock Exchange in June. There is one notable geographic gap. FORTUNE began canvassing Eastern Europe after the collapse of communism in 1990. Despite feverish development and privatization throughout the region, no company has made it onto the Global 500 yet.

BOX:

One vast region of the world is still unrepresented on the Global 500. Can you name it?

CHART: NOT AVAILABLE CREDIT: NO CREDIT CAPTION: FORTUNE'S GLOBAL 500 WITHIN COUNTRIES