Question: In what year was the hotel, founded by E. S. Babcock, designated a National Historic Landmark?

Context articles: E. S. Babcock
Maggie L. Walker National Historic Site
Harry S. Truman Historic District
Hotel del Coronado
List of U.S. National Historic Landmarks by state
Hinchliffe Stadium
Guthrie Historic District (Guthrie, Oklahoma)
Printing House Row District
Litchfield Historic District
San Juan Bautista State Historic Park

E. S. Babcock (May 1, 1848 – September 1, 1922) was an industrialist, tycoon, businessman, and entrepreneur.
 He is most famous for founding the Hotel del Coronado.
The Maggie L. Walker National Historic Site is a United States National Historic Landmark and a National Historic Site located at 110½ E. Leigh Street on "Quality Row" in the Jackson Ward neighborhood of Richmond, Virginia.
 The site was designated a U.S. National Historic Landmark in 1975.
 The National Historic Site was established in 1978 to tell the story of the life and work of Maggie L. Walker (1867-1934), the first woman to serve as president of a bank in the United States.
 It was built by George W. Boyd, father of physician, Sarah Garland Boyd Jones.
 The historic site protects the restored and originally furnished home of Walker.
 Tours of the home are offered by National Park Service rangers.
The Harry S. Truman Historic District is a National Historic Landmark District encompassing sites closely associated with US President Harry S. Truman in Independence, Missouri.
 It includes the Truman Home at 219 North Delaware, Truman's home for much of his adult life and now a centerpiece of the Harry S. Truman National Historic Site, and the Truman Presidential Library.
 The district was listed on the National Register of Historic Places in 1971, and was designated a National Historic Landmark in 1974.
 When first listed, the district included only the two buildings and a corridor joining them.
 It was substantially enlarged in 2011 to include more sites and the environment in which Truman operated while living in Independence.
Hotel del Coronado (also known as The Del and Hotel Del) is a historic beachfront hotel in the city of Coronado, just across the San Diego Bay from San Diego, California.
 It is one of the few surviving examples of an American architectural genre: the wooden Victorian beach resort.
 It is the second largest wooden structure in the United States (after the Tillamook Air Museum in Tillamook, Oregon) and was designated a National Historic Landmark in 1977 and a California Historical Landmark in 1970.
The United States National Historic Landmark Program is designed to recognize and honor the nation's cultural and historical heritage.
 The program was formally inaugurated with a series of listings on October 9, 1960; as of February 16, 2017, there are 2,596 designated landmarks.
 A National Historic Landmark (NHL) is generally a building, district, object, site, or structure, that is officially recognized by the United States government for its national historical significance.
 A National Historic Landmark District (NHLD) is a historic district that is recognized as an NHL.
 Its geographic area may include contributing properties that are buildings, structures, sites or objects, and it may include non-contributing properties.
Hinchliffe Stadium ( ) is a 10,000-seat stadium located in Paterson, New Jersey, USA.
 The venue was completed in 1932 and sits on a dramatic escarpment above Paterson's National Historic Landmark Great Falls, and surrounded by the city's National Landmark Historic District, the first planned industrial settlement in the nation (chartered 1792).
 It is one of only a handful of stadiums surviving nationally that once played host to significant Negro league baseball during America's Jim Crow era.
 The stadium was designated a National Historic Landmark in March 2013 and a Paterson Historic Landmark in May 2013.
 In December 2014 legislation passed in the United States Congress to in include the stadium in the Great Falls National Landmark District.
The Guthrie Historic District (GHD) is a National Historic Landmark District encompassing the commercial core of Guthrie, Oklahoma, US.
 According to its National Historic Landmark Nomination it is roughly bounded by Oklahoma Avenue on the north, Broad Street on the east, Harrison Avenue on the south, and the railroad tracks on the west; it also includes 301 W. Harrison Avenue.
 The National Historic Landmarks Program on-line document describes the boundaries as "14th Street, College Avenue, Pine Street and Lincoln Avenue.
 One building, the Logan County Courthouse, is at 301 E. Harrison Avenue, outside the main boundaries of the GHD," This article relies on the former source, which is more detailed.
 According to the 1998 nomination, the proposed district covered 31 acres .
 The nomination included 112 resources, classed as 69 contributing buildings, 38 non-contributing buildings, 1 non-contributing structure and 3 noncontributing objects.
 It was declared a National Historic Landmark in 1999 for its historic significance as the first capital of the Oklahoma Territory and of Oklahoma.
The Printing House Row District is a National Historic Landmark District encompassing four architecturally important buildings on the 300 through 500 blocks of South Dearborn, South Federal and South Plymouth streets in the Loop community area of Chicago, Illinois.
 It was listed on the National Register of Historic Places as South Dearborn Street – Printing House Row Historic District and listed as a National Historic Landmark as South Dearborn Street – Printing House Row North Historic District on January 7, 1976.
 The district was designated a Chicago Landmark on May 9, 1996.
 The district includes the Monadnock Building, the Manhattan Building, the Fisher Building, and the Old Colony Building.
 The district overlaps significantly with the Printers Row neighborhood, and is not the same as South Loop Printing House District.
Litchfield Historic District, in Litchfield, Connecticut, is a National Historic Landmark District designated in 1968 as a notable and well-preserved example of a typical late 18th century New England village.
 As a National Historic Landmark, it is listed on the National Register of Historic Places (NRHP).
 It is the core area of a larger NRHP-listed historic district that includes the entire borough of Litchfield and was designated a state historic district in 1959.
San Juan Bautista Plaza Historic District, also known as San Juan Bautista State Historic Park is a historic district in San Juan Bautista, California, United States, that is a National Historic Landmark and a California state historic park.
 It includes the Mission San Juan Bautista, the Jose Castro House (another National Historic Landmark), and several other buildings.
 It became a State Park in 1933 and was declared a National Historic Landmark in 1970.