Question: What is the 2015 population of the city in which Silberturm was located. 

Context articles: Silberturm
Purcellville, Virginia
Skagway, Alaska
Owensboro, Kentucky
Rochester, Minnesota
Paris
Frankfurt
San Mateo, California
Federal Way, Washington
Boca Raton, Florida

Silberturm (English: "Silver Tower" ), formerly known as Dresdner-Bank-Hochhaus and Jürgen-Ponto-Hochhaus, is a 32-storey, 166.3 m futurist skyscraper in the Bahnhofsviertel district of Frankfurt, Germany.
 It was the tallest building in Germany from 1978 until 1990.
 Until 2009 it was part of the headquarters of Dresdner Bank, one of Germany's largest banks until its merger with Commerzbank in 2009.
 As of 2012 the main tenant is Deutsche Bahn.
Purcellville is a town in Loudoun County, Virginia, United States.
 The population was 9,232 according to the United States Census 2015 Population Estimate (as of July 1, 2015).
 Purcellville is the major population center for western Loudoun and the Loudoun Valley.
 Today , many of the older structures remaining in Purcellville reflect the Victorian architecture popular during the early 20th century.
 Patrick Henry College is located in the town.
The Municipality and Borough of Skagway ( ) is a first-class borough in Alaska on the Alaska Panhandle.
 As of the 2010 census, the population was 920.
 Estimates put the 2015 population at 1,057 people.
 The population doubles in the summer tourist season in order to deal with more than 900,000 visitors.
 Incorporated as a Borough on June 25, 2007, it was previously a city (urban Skagway located at ) in the Skagway-Yakutat-Angoon Census Area (now the Hoonah–Angoon Census Area).
Owensboro is a home rule-class city in and the county seat of Daviess County, Kentucky, United States.
 It is the fourth-largest city in the state by population.
 Owensboro is located on U.S. Route 60 about 107 mi southwest of Louisville, and is the principal city of the Owensboro metropolitan area.
 The 2015 population was 59,042.
 The metropolitan population was estimated at 116,506.
Rochester is a city in the U.S. State of Minnesota and is the county seat of Olmsted County.
 Located on the Zumbro River's south fork, the city has a population of 106,769 according to the 2010 United States Census.
 The U.S. Census Bureau estimated that the 2015 population was 112,225.
 It is Minnesota's third-largest city and the largest city located outside of the Minneapolis-St.
 Paul-Bloomington Metropolitan Statistical Area.
 As of 2015, the Rochester metropolitan area has a population of 213,873.
 It is the home of Mayo Clinic and one of IBM's largest facilities.
Paris (] ) is the capital and most populous city of France, with an administrative-limits area of 105 km2 and a 2015 population of 2,229,621.
 The city is a commune and department, and the capital-heart of the 12,012 km2 Île-de-France "region" (colloquially known as the 'Paris Region'), whose 12,142,802 2016 population represents roughly 18 percent of the population of France.
 By the 17th century, Paris had become one of Europe's major centres of finance, commerce, fashion, science, and the arts, a position that it retains still today.
 The Paris Region had a GDP of €649.6 billion (US $763.4 billion) in 2014, accounting for 30.4 percent of the GDP of France.
 According to official estimates, in 2013-14 the Paris Region had the third-highest GDP in the world and the largest regional GDP in the EU.
Frankfurt, officially Frankfurt am Main (Literally "Frankfurt on the Main", ] ), is a metropolis and the largest city in the German state of Hesse and the fifth-largest city in Germany, with a 2015 population of 732,688 within its administrative boundaries, and 2.3 million in its urban area.
 The city is at the centre of the larger Frankfurt Rhine-Main Metropolitan Region, which has a population of 5.5 million and is Germany's second-largest metropolitan region after Rhine-Ruhr.
 Since the enlargement of the European Union in 2013, the geographic centre of the EU is about 40 km to the east of Frankfurt's CBD, the Bankenviertel.
 Frankfurt is culturally and ethnically diverse, with around half of the population, and a majority of young people, having a migration background.
 A quarter of the population are foreign nationals, including many expatriates.
San Mateo ( ; Spanish for "Saint Matthew") is a city in San Mateo County, California, located in the high-tech enclave of Silicon Valley in the San Francisco Bay Area.
 With a population of 97,207 as of the 2010 census, it is one of the larger suburbs on the San Francisco Peninsula, located between Burlingame to the north, Foster City and San Francisco Bay to the east, Belmont to the south, and Highlands-Baywood Park and Hillsborough to the west.
 The 2015 population was estimated to be 103,536.
 San Mateo was incorporated in 1894.
Federal Way is a city in King County, Washington, United States.
 It is a coastal city inside the Seattle metropolitan area.
 Its southwestern boundary is NE Tacoma Puget Sound, to the south is the cities of Milton, then Fife, then Tacoma.
 It is bordered by Des Moines and Kent on the northeast, Auburn as well as the town of Lakeland North and Lakeland South in unincorporated King County on the east, Milton on the south, and Tacoma as well as Fife Heights and Dash Point in unincorporated Pierce County on the southwest.
 The population was 95,171 at the 2015 United States Census.
 Federal Way is currently the 9th largest city in Washington State and the 5th largest in King County, according to the Census Bureau's 2015 population estimate.
Boca Raton ( ; ] ) is the southernmost city in Palm Beach County, Florida, United States, first incorporated on August 2, 1924 as "Bocaratone," and then incorporated as "Boca Raton" in 1925.
 The 2015 population estimated by the U.S. Census Bureau was 93,235.
 However, approximately 200,000 people with a Boca Raton postal address reside outside its municipal boundaries.
 Such areas include newer developments like West Boca Raton.
 As a business center, the city also experiences significant daytime population increases.
 It is one of the wealthiest communities in South Florida.
 Boca Raton is 43 mi north of Miami and is a principal city of the Miami metropolitan area, which was home to an estimated 6,012,331 people at the 2015 census.