Question: What is the population of the area where Dennis Gibson was born?

full_context: Document 1: Chicago Bears: Mike Ditka, a tight end for the Bears from 1961 to 1966, was hired to coach the team by George Halas in 1982. His gritty personality earned him the nickname ``Iron Mike ''. In the 1985 season the fire in the Bears -- Packers rivalry was relit when Ditka used 315 pound defensive tackle`` Refrigerator'' Perry as a running back in a touchdown play at Lambeau Field, against the Packers. The Bears won their ninth NFL Championship, first since the AFL - NFL merger, in Super Bowl XX after the 1985 season in which they dominated the NFL with their then - revolutionary 46 defense and a cast of characters that recorded the novelty rap song ``The Super Bowl Shuffle ''. The season was notable in that the Bears had only one loss, the`` unlucky 13th'' game of the season, a Monday night affair in which they were defeated by the Miami Dolphins. At the time, much was made of the fact that the 1972 Dolphins were the only franchise in history to have had an undefeated season and post-season. The Dolphins came close to setting up a rematch in the Super Bowl, but lost to the New England Patriots in the AFC title game. ``The Super Bowl Shuffle ''was videotaped the day after that Monday night loss in Miami.
Document 2: Keith Fahnhorst: Fahnhorst's younger brother Jim Fahnhorst played linebacker in the USFL and for the 49ers from 1984 to 1990. The brothers were teammates on the 1984 49ers team that won Super Bowl XIX and finished with a 15-1 record.
Document 3: Derrick Gibson: Derrick Gibson (born March 22, 1979 in Miami, Florida) is a former American football safety who played his entire career for the Oakland Raiders. He was drafted by the Raiders in the first round (28th overall) in the 2001 NFL Draft. He played college football at Florida State.
Document 4: Elvis Grbac: Although Grbac initially wished to continue his football career at Ohio State, he changed his mind when the Buckeyes fired head coach Earl Bruce and opted instead to join Howard at the University of Michigan, where he played college football from 1989 to 1992. He led the Wolverines to a Gator Bowl in 1991, three Rose Bowls in 1990 and 1993 and 1992 and is best remembered for throwing to wide receiver Desmond Howard during the latter's Heisman-winning season in 1991. In 1991 Grbac's pass to Howard sealed a 24-14 victory over Notre Dame. In that game Grbac completed 20-of-22 passes, a record for a Notre Dame opponent. He finished his career at Michigan as the school's all-time leader in passing attempts (835), completions (522), passing yards (6,460) and passing touchdowns (71). These marks were later broken by John Navarre in 2003 and surpassed by Chad Henne in 2006–2007.
Document 5: Gary Reasons: Gary Phillip Reasons (born February 18, 1962) is a former American football linebacker for the New York Giants of the National Football League, winning Super Bowl XXI and Super Bowl XXV as a member of the team.
Document 6: Saylorville, Iowa: Saylorville is a census-designated place (CDP) in Polk County, Iowa, United States. The population was 3,301 at the 2010 census. It is part of the Des Moines–West Des Moines Metropolitan Statistical Area. The Saydel Community School District is located in this area. The unincorporated community of Marquisville is in this area.
Document 7: Des Moines metropolitan area: The Des Moines metropolitan area, officially known as the Des Moines -- West Des Moines, IA Metropolitan Statistical Area (MSA), consists of five counties in central Iowa, United States: Polk, Dallas, Warren, Madison, and Guthrie. The 2010 census population of these counties was 569,633, and the 2017 estimated population was 645,911.
Document 8: Joe Gibson: Billy Joe Gibson (June 28, 1919October 19, 2002) was an American football defensive back and end in the National Football League for the Cleveland Rams (1942, 1944) and the Washington Redskins (1943). Gibson also played in the All-America Football Conference for the Brooklyn Dodgers. He played college football at the University of Tulsa.
Document 9: Dennis Gibson (American football): Dennis Michael Gibson (born February 8, 1964 in Des Moines, Iowa) is a former American football linebacker who played in the National Football League from 1987-1995 for the Detroit Lions and the San Diego Chargers. Perhaps his most memorable moment came in the , when he sent the Chargers to the Super Bowl by lunging to block a 4th down pass attempt from Pittsburgh Steelers quarterback Neil O'Donnell in the end zone to win the game.
Document 10: Cedar Rapids, Iowa: As of the 2010 United States Census, the city population was 126,326. The estimated population of the three - county Metropolitan Statistical Area, which includes the nearby cities of Marion and Hiawatha, was 255,452 in 2008. Cedar Rapids is an economic hub of the state, located in the core of the Interstate 380.
Document 11: Middletown, Iowa: Middletown is a city in Des Moines County, Iowa, United States. The population was 318 at the 2010 census. It is part of the Burlington, IA–IL Micropolitan Statistical Area.
Document 12: Barry Sanders: Barry Sanders (born July 16, 1968) is a former American football running back. He played professionally for the Detroit Lions of the National Football League (NFL). A Pro Bowl invitee in each of his ten NFL seasons and two-time NFL Offensive Player of the Year, Sanders led the league in rushing yards four times and established himself as one of the most elusive runners in pro football with his quickness and agility. In 2007, he was ranked by NFL Network's "NFL Top 10" series as the most elusive runner in NFL history, and also topped its list of greatest players never to play in a Super Bowl. He is often regarded as one of the greatest running backs in NFL history.
Document 13: Johnston, Iowa: Johnston is a city in Polk County, Iowa, United States. The population was 17,278 in the 2010 census, an increase of almost 100% from the 8,649 population in the 2000 census. It is part of the Des Moines–West Des Moines Metropolitan Statistical Area.
Document 14: Des Moines, Iowa: On September 22, 1851, Des Moines was incorporated as a city; the charter was approved by voters on October 18. In 1857, the name ``Fort Des Moines ''was shortened to`` Des Moines'', and it was designated as the second state capital, previously at Iowa City. Growth was slow during the Civil War period, but the city exploded in size and importance after a railroad link was completed in 1866.
Document 15: Des Moines, Iowa: Age spread: 24.8% under the age of 18, 10.6% from 18 to 24, 31.8% from 25 to 44, 20.4% from 45 to 64, and 12.4% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 93.8 males. For every 100 females age 18 and over, there were 90.5 males.
ground_truth: 645,911
sub_queries: Dennis Gibson >> place of birth Answer: Des Moines
what is the population of the Des Moines area Answer: 645,911