Miami ? Tiger Woods might be the most recognized athlete on the planet. Phil Mickelson’s Masters triumph spilled beyond the sports pages. Annika Sorenstam and Michelle Wie draw huge crowds.

But there’s a side to golf’s populist boom that has industry officials scratching their heads — emptier fairways. The number of recreational rounds has decreased each of the past four years.

“We need to get people playing golf again,” said M.G. Orender, president of the PGA of America.

That’s the purpose behind the “Play Golf America” campaign, launched this month in an effort to reach the 17 million Americans who say they’re interested in taking up the game, plus some 14 million occasional golfers.

According to the National Golf Foundation, recreational rounds have decreased by 5 percent the past two years, from 518 million in 2001 to 495 million last year.

The initiative’s launch coincides with the PGA’s annual Free Lesson Month. Some 4,700 teaching pros nationwide are offering free 10-minute lessons this month.

A list of instructors can be found at the www.playgolf-america.com website.