There are some things that you don't want to bet against -- such as gravity or increasingly bizarre hairstyles on Britney Spears. Another is the stunning growth of wireless services in developing nations. With its third-quarter earnings, America Movil (NYSE:AMX) showed once again that the spring of near-30% growth in wireless services in Latin America is still flowing.

The company that, along with Telmex (NYSE:TMX) and other interests, helped vault billionaire Carlos Slim Helu to the title of richest person in the world, reported revenue growth of 29.8% to $7.2 billion for the quarter. Earnings before interest, taxes, depreciation, and amortization (EBITDA) rose 44.6%, but net earnings of $1.03 billion were actually 2% lower than last year, so obviously there's something missing in the middle.

The big bite out of the bottom line came from a few areas -- one was increased depreciation expense and another was a bigger tax bite. The higher depreciation charges stem from removing equipment and services based on an old technical standard, called TDMA, in some countries. Other operators, such as AT&T (NYSE:T) in the U.S., have moved to retire these networks and move users to newer service platforms.

Chile was the only market where America Movil had a net reduction in wireless subscribers for the quarter, characterizing the loss as a "cleansing" of the base there. But the company is generally holding its own against main rival Telefonica (NYSE:TEF), growing its wireless subscriber base 4.5% in the quarter by adding 6.2 million new subscribers. With a total of 143.4 million wireless subscribers across more than a dozen countries, America Movil shares the scale of global behemoths China Mobile (NYSE:CHL) and Vodafone (NYSE:VOD).

America Movil's stock took a dip after the earnings release, but shares still sit nearly 50% higher than where they started in 2007. The lighter-than-expected earnings and continued rise in the stock will make America Movil look more expensive to investors. But compared with its peers, I still find this giant company a cheaper way to tap the booming growth of wireless services in emerging markets.

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Fool contributor Dave Mock is a hero to some and an idiot to others. He owns no shares of companies mentioned in this article. Dave is the author of The Qualcomm Equation. The Fool's disclosure policy will pick you for its team, even if you can't field the easiest of grounders.