Question: What is the population of the metropolitan area where Natasha Kaiser-Brown was born?

full_context: Document 1: Natasha Kaiser-Brown: Kaiser-Brown was born in Des Moines, Iowa. In high school, she was a nine-time state champion for Des Moines Roosevelt and is the previous record-holder for the 100 meter and sprint medley relay events (both broken in the 2018 track season).
Document 2: Shana Woods: Shana Woods (born July 7, 1988 in Bellflower, California) is an American track and field athlete. She holds the current national high school record in the multiple event heptathlon, which she set while attending Long Beach Polytechnic High School in Long Beach, California. She has exhibited proficiency in a variety of events. While still a sophomore at Long Beach Poly, she joined her teammates, including senior Shalonda Solomon in setting national high school records in the 4 × 400 metres relay, 4 × 200 metres relay and indoor 4 × 400 metres relay. All those records still stand. The indoor record also counts as the current U.S. Junior record.
Document 3: 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.
Document 4: 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 5: 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 6: 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 7: Kara Denby: Denby was a 24-time All-American at Auburn University between the years of 2004 and 2008. In 2006 and 2007 the Auburn University Women's Swimming and Diving team took home the NCAA National Team title.
Document 8: 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 9: Iowa High School Athletic Association: Iowa High School Athletic Association Abbreviation IHSAA Legal status Association Purpose Athletic / Educational Headquarters 1605 South Story St. Boone, Iowa 50036, United States Region served Iowa Membership 375 + high schools Official language English Executive Director Richard Wulkow Affiliations National Federation of State High School Associations Staff 17 Website iahsaa.org Remarks (515) 432 - 2011
Document 10: Namibia: Inline hockey was first played in 1995 and has also become more and more popular in the last years. The Women's inline hockey National Team participated in the 2008 FIRS World Championships. Namibia is the home for one of the toughest footraces in the world, the Namibian ultra marathon. The most famous athlete from Namibia is Frankie Fredericks, sprinter (100 and 200 m). He won four Olympic silver medals (1992, 1996) and also has medals from several World Athletics Championships. He is also known for humanitarian activities in Namibia and beyond.
Document 11: University of Kansas: The school's sports teams, wearing crimson and royal blue, are called the Kansas Jayhawks. They participate in the NCAA's Division I and in the Big 12 Conference. KU has won thirteen National Championships: five in men's basketball (two Helms Foundation championships and three NCAA championships), three in men's indoor track and field, three in men's outdoor track and field, one in men's cross country and one in women's outdoor track and field. The home course for KU Cross Country is Rim Rock Farm. Their most recent championship came on June 8, 2013 when the KU women's track and field team won the NCAA outdoor in Eugene, Oregon becoming the first University of Kansas women's team to win a national title.
Document 12: Indianola, Iowa: Indianola is a city in Warren County, Iowa, United States, 18 miles south of Des Moines, Iowa. The population was 14,782 at the 2010 census. It is the county seat of Warren County.
Document 13: 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 14: 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 15: Kaye Hall: Hall was born in Tacoma, Washington, and attended Woodrow Wilson High School in Tacoma. She trained with the Tacoma Swim Club with coach Dick Hannula. Hall made her international debut at the 1967 Pan American Games in Winnipeg, where she won a silver medal in the 100-meter backstroke behind Canadian gold medalist Elaine Tanner. In December 1967, she became the first woman to swim the 100-yard backstroke in under one minute.
ground_truth: 645,911
sub_queries: Natasha Kaiser-Brown >> place of birth Answer: Des Moines
what is the population of the Des Moines area Answer: 645,911