A store remains closed in the Santurce sector in San Juan, March 11, 2014. Puerto Rico on Tuesday sold $3.5 billion of junk-rated bonds at a surprisingly low tax-free interest rate under 9 percent, which was still high enough to tempt investors to snap up the bonds despite the Caribbean island's difficult cash position. Worries linger about Puerto Rico's economy, which has been shrinking nearly non-stop since 2006 and suffers from a dwindling population, high unemployment now topping 15 percent, and chronic government budget deficits. REUTERS/Ana Martinez (PUERTO RICO - Tags: POLITICS BUSINESS)