Coca-Cola Co. reported yesterday an 11-percent drop in quarterly net income, hurt by sluggish sales of soft drinks in North America, its largest market.

The world?s largest soft-drink maker earned $1 billion, or 42 cents a share, in the first quarter, compared with $1.13 billion, or 46 cents a share, a year earlier. Revenue increased to $5.27 billion from $5.08 billion.

Excluding special items, Coke said earnings would have been 47 cents a share. Analysts on average had forecast a profit of 43 cents per share on sales of $5.15 billion, according to Reuters Estimates.

Coca-Cola?s sales, as measured by unit case volume, rose 3 percent, boosted by double-digit growth in China, Brazil and other emerging markets. Volume in North America, Coca-Cola?s most important market, was flat in the period.

Reigniting sales of core brands, such as the flagship Coke Classic product, has been a top priority in North America since the company embarked on a sweeping restructuring of its global operations more than five years ago.