The National Park Service said that 207,352 people visited its two sites in Iowa in 2012, spending $11.5 million in area economies and supporting 176 jobs. According to a release, Park Service tourism returns $10 for every $1 invested in the agency's sites. The sites are Effigy Mounds National Monument in Harpers Ferry and Herbert Hoover National Historic Site in West Branch. The spending analysis was conducted by U.S. Geological Survey economists for the National Park Service.