It says that through various activities — extortion, usury, contraband, robberies, gambling and Internet piracy — organized crime accounts for 7 percent of Italy’s gross domestic product.
The "it" above refers to a study conducted by confesercenti, an association of small businesses. More from NYT here.
Next time when you visit Italy, make sure you pronounce the word "pizza" in the right way and not "pizzo" which means protection money given to the mafia.
If you want to learn more about the economics of mafia, start at this classic treatment on the topic.