The percentage of the U.S. population living in counties close to a coastline has reached nearly 40 percent in recent years, which means more of us are exposed to extreme—and very costly—coastal storms such as Sandy and Isaac, according to a government report released Monday. These coastal counties account for less than 10 percent of the U.S. land area, excluding Alaska, yet this population is growing. "The real issue is the density, the density is growing enormously," the report's editor, Kristin Crossett of the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service, told NBC News. If the current trends continue, the report notes, the U.S. coastal population will reach 134 million in 2020, up from 123 million in 2010. But it’s not all beach houses and waterfront condos. Many of the properties in direst need of assistance are owned by people who can't afford to move.