Question: The last living pilot of the X-15 program was inducted into the National Aviation Hall of Fame in what year?

Context articles: Nellie Zabel Willhite
Joe Engle
Dwane Wallace
Russell W. Meyer Jr.
Sherman Fairchild
Charlie Johnson (pilot)
Bud Anderson
Robert L. Rasmussen
Sean D. Tucker
Albert Lee Ueltschi

Eleanor "Nellie" Zabel Willhite (Born November 22, 1892 in Box Elder, South Dakota – September 2,1991) was the first deaf woman to earn a pilot’s license, as well as South Dakota’s first female pilot.
 Willhite became deaf at age two due to measles.
 She earned her pilot's license in 1928.
 She was a founding member of the Ninety-Nines, an organization which was founded in 1929 with 99 female pilots as founding members, and is dedicated to the advancement of aviation and support for women in aviation.
 Willhite started the first South Dakota chapter of the Ninety-Nines in 1941.
 She worked as a commercial pilot until 1944 (the first and last deaf person to do so), carrying airmail.
 She also worked as a barnstormer, specializing in flour bombing and balloon racing.
 She was inducted into the South Dakota Aviation Hall of Fame shortly before her death in 1991, and her plane the "Pard" is now on display at the Southern Museum of Flight in Birmingham, Alabama.
Joe Henry Engle (born August 26, 1932), (Maj Gen, USAF, Ret.)
, is an American pilot who served in the United States Air Force, test pilot for the North American X-15 program, aeronautical engineer, and a former NASA astronaut.
 As of 2017, he is the last living pilot of the X-15 program.
Dwane Leon Wallace (October 29, 1911 – December 21, 1989) was the President and/or Chairman of the Board of the Cessna Aircraft Company from 1935 until the 1970s, having then continued on the board as a director and consultant into the 1980s.
 He is generally credited with leading the company from a minor role in the aviation industry to overwhelming dominance—ultimately the world's largest and most diverse general aviation manufacturer with the highest volume of aircraft production.
 He later became known as the "Quiet Giant of Aviation", and was posthumously inducted into the National Aviation Hall of Fame in 2012.
Russell W. "Russ" Meyer Jr. (born 1932 in Davenport, Iowa, United States) is the Chairman Emeritus and former Chief Executive Officer (CEO) of the Cessna Aircraft Company.
 He was awarded the Wright Brothers Memorial Trophy, the Collier Trophy on two separate occasions (once jointly with Cessna), and the Meritorious Service Award from the National Business Aircraft Association (NBAA).
 In 2009, he became inducted into the National Aviation Hall of Fame.
Sherman Mills Fairchild (April 7, 1896 – March 28, 1971) was an American businessman, investor and inventor.
 He founded over 70 companies, including Fairchild Aircraft, Fairchild Industries, Fairchild Aviation Corporation, and Fairchild Camera and Instrument.
 Fairchild made significant contributions to the aviation industry and was inducted into the National Aviation Hall of Fame in 1979.
 His Fairchild Camera & Instrument Corporation, Semiconductor Division company played a defining role in the development of Silicon Valley.
 He held over 30 patents for products ranging from the silicon semiconductor to the 8-mm home sound motion-picture camera.
 Fairchild is also responsible for inventing the first synchronized camera shutter and flash as well as developing new technologies for aerial cameras that were later used on the Apollo Missions.
Charles (Charlie) Johnson is a former president of Cessna Aircraft.
 He was born in 1942 in Georgia and grew up in Memphis.
 He has always been passionate about technology.
 Because he was also passionate about flight, he joined the Air Force.
 He fought in the Vietnam War flying the T-33, T-37, T-38, and the F-105.
 After the Vietnam War he continued with his love of flying.
 Johnson was a personal pilot for Arnold Palmer.
 After this he became a test pilot for Learjet.
 Soon after he rose through the ranks of Cessna to President and COO of Cessna Aircraft.
 Johnson joined Bye Aerospace in 2014 and was inducted into the Colorado Aviation Hall of Fame the same year.
 He has just recently been inducted into the Kansas Aviation Hall of Fame.
 Johnson continues to fly and has a love of cars.
Clarence Emil "Bud" Anderson (born January 13, 1922) is a retired officer in the United States Air Force and a "triple ace" in World War II.
 During the war he was the highest scoring ace in his P-51 Mustang squadron.
 This was the same squadron as well known test pilot (and first pilot to break the sound barrier) and ace Chuck Yeager, and they have remained lifelong close friends.
 Towards the end of Anderson's two combat tours in Europe in 1944 he was promoted to major at age 22, an extremely young age even for a highly effective officer in wartime.
 After the war Anderson became a well regarded fighter test pilot, and a fighter squadron and wing commander.
 He served his wing commander tour in combat in the Vietnam War.
 He retired as a full colonel in 1972, after which he worked in flight test management for McDonnell Douglas.
 A member of the National Aviation Hall of Fame, Col. Anderson has remained a sought after speaker at aviation and military events well into his 90's.
Robert L. “Bob” Rasmussen (born May 26, 1930 in Rio Vista, California), is a noted military artist; a retired Captain of the United States Navy; a former career naval aviator, primarily in the F-8 Crusader; a former member of the U.S. Navy Flight Demonstration Squadron, the Blue Angels, and Director of the National Naval Aviation Museum at NAS Pensacola, Florida.
 His Vietnam war experiences, including surviving the fire aboard USS "Oriskany" , have been documented in several books.
 A prolific artist, Rasmussen has created hundreds of Naval Aviation paintings in watercolor, oil and acrylic.
 His bronze sculptures include the design of the Spirit of Naval Aviation, displayed at the front entrance of the National Museum of Naval Aviation, Pensacola, Florida, the Alan Shepard memorial heroic figure at the Astronaut Hall of Fame, and the World War II and Korean War memorials in Pensacola, Florida.
 His works have been displayed around the country, including the National Air and Space Museum in Washington, D.C., the National Naval Aviation Museum in Pensacola, Florida, and the NASA Museum at Cape Canaveral, Florida.
 Rasmussen is the recipient of the R.G. Smith Award for Excellence in Naval Aviation Art, was inducted into the Naval Aviation Hall of Honor in 2008, and was awarded the Navy Superior Civilian Service Award on 24 September 2009.
Sean Doherty Tucker (born April 27, 1952) is an American aerobatic pilot who is sponsored by the Oracle Corporation and performs in airshows worldwide as Team Oracle.
 Tucker has won several airshow championship competitions throughout his career and was inducted into the National Aviation Hall of Fame in 2008.
 He currently serves as Chairman of the Experimental Aircraft Association's Young Eagles program.
Albert Lee "Al" Ueltschi (May 15, 1917 – October 18, 2012) is considered the father of modern flight training and was the founder of FlightSafety International.
 Ueltschi was once personal pilot to Juan Trippe and an associate to Charles Lindbergh.
 On July 21, 2001, he was enshrined at Dayton, Ohio, in the National Aviation Hall of Fame class of 2001, along with test pilot Joe Engle, United States Air Force flying ace Marion Carl, and USAF ace Robin Olds.
 In 2013, "Flying" magazine ranked Ueltschi number 13 on its list of the "51 Heroes of Aviation".