Question: What 58th quadrennial American presidential election did Bernie Sanders announce his candidacy for the Democratic nomination for President of the United States?

Context articles: United States presidential election, 2016
United States presidential election, 1892
Political positions of Bernie Sanders
Bernie Singles
United States presidential election, 2012
United States presidential election, 1964
Bernie Sanders' Dank Meme Stash
The People for Bernie Sanders
Tom Fiegen
United States presidential election, 1960

The United States presidential election of 2016 was the 58th quadrennial American presidential election, held on Tuesday, November 8, 2016.
 In a surprise victory, the Republican ticket of businessman Donald Trump and Indiana Governor Mike Pence defeated the Democratic ticket of former First Lady, U.S. Senator of New York and Secretary of State Hillary Clinton and U.S. Senator from Virginia Tim Kaine.
 Trump took office as the 45th President, and Pence as the 48th Vice President, on January 20, 2017.
 Concurrent with the presidential election, Senate, House, and many gubernatorial and state and local elections were also held on November 8.
The United States presidential election of 1892 was the 27th quadrennial presidential election, held on Tuesday, November 8, 1892.
 It witnessed a re-match of the closely contested presidential election in 1888.
 Former Democratic President Grover Cleveland and incumbent Republican President Benjamin Harrison both ran for election to a second term.
 In 1888, Cleveland won the popular vote over Harrison, but lost in the electoral college.
 In a re-match, Cleveland won both the popular and electoral vote, thus becoming the first and to date only person in American history to be elected to a second, non-consecutive presidential term.
 The new Populist Party, formed by groups from The Grange, the Farmers' Alliances, and the Knights of Labor, also fielded a ticket; they polled best in the West, winning in five states and taking a total of 22 electoral votes.
Bernard Sanders is the junior United States Senator from Vermont, a former member of the U.S. House of Representatives from Vermont's at-large congressional district, and former Mayor of Burlington, Vermont.
 He has taken positions on many political issues, both through his public comments and based on his Congressional voting record.
 In 2015, he announced his candidacy for the Democratic nomination for President of the United States in the 2016 election.
Bernie Singles is an online dating service where members can connect based on a mutual interest in American politician and junior United States senator Bernie Sanders.
 Sanders was a candidate for the Democratic nomination for President of the United States in the 2016 U.S. presidential election.
 As of October 8, 2016, it had 20,834 registered users.
The United States presidential election of 2012 was the 57th quadrennial American presidential election.
 It was held on Tuesday, November 6, 2012.
 The Democratic nominee, incumbent President Barack Obama, and his running mate, Vice President Joe Biden, were elected to a second term, defeating the Republican nominee, former Governor of Massachusetts Mitt Romney and his running mate, Representative and future House Speaker Paul Ryan of Wisconsin.
The United States presidential election of 1964 was the 45th quadrennial presidential election.
 It was held on Tuesday, November 3, 1964.
 Democratic candidate and incumbent President Lyndon B. Johnson had come to office less than a year earlier following the assassination of his predecessor John F. Kennedy.
 Johnson, who had successfully associated himself with Kennedy’s popularity, won 61.1% of the popular vote, the highest win by a candidate since James Monroe’s re-election in 1820.
 It was the most lopsided US presidential election in terms of popular votes, and the tenth-most lopsided presidential election in the history of the United States in terms of electoral votes.
 No candidate for president since has equalled or surpassed Johnson’s percentage of the popular vote, and since 1820, only Abraham Lincoln in 1864, Franklin D. Roosevelt in 1936, Richard Nixon in 1972 and Ronald Reagan in 1980 and 1984 have won by a greater electoral vote margin.
Bernie Sanders' Dank Meme Stash is a Facebook group where members can share and discuss Internet memes relating to American politician and United States senator from Vermont Bernie Sanders.
 Sanders was a candidate for the Democratic nomination for President of the United States in the 2016 U.S. presidential election.
 As of May 18, 2017, the group had about 440,000 members.
The People for Bernie Sanders (also known as People for Bernie) is a grassroots movement which arose to support the candidacy of Bernie Sanders during the Bernie Sanders presidential campaign, 2016.
 People for Bernie, independent from the official campaign and largely organized via social media, grew to over 1 million followers on Facebook.
 Founded by veterans of Occupy Wall Street, People for Bernie became a key organizing force for progressives during the 2016 US Presidential Campaign, including coining the hashtag #feelthebern.
 Linked to other progressive groups like the National Nurses United and Democratic Socialists of America, People for Bernie became recognized for its role in mobilizing Sanders supporters and its innovative organizing strategies.
Thomas Lewis "Tom" Fiegen (born October 2, 1958) is an American attorney and Democratic Party politician.
 He served in the Iowa State Senate from 2001 to 2003.
 He sought the Democratic nomination in the 2010 U.S. Senate election in Iowa but came in third against Roxanne Conlin who won the primary, with Bob Krause coming in second.
 Fiegen again sought the Democratic nomination in the 2016 U.S. Senate election in Iowa, repeating his third-place showing.
 Fiegen endorsed Bernie Sanders for president prior to Sanders' endorsement of fellow candidate Hillary Clinton.
The United States presidential election of 1960 was the 44th quadrennial presidential election, held on Tuesday, November 8, 1960.
 The Republican Party nominated incumbent Vice President Richard Nixon, while the Democratic Party nominated John F. Kennedy, U.S. Senator from Massachusetts.
 The incumbent President, Republican Dwight D. Eisenhower, was not eligible for re-election after being elected the maximum two times allowed by the Twenty-second Amendment; he was the first President denied the choice to run for a third term by that amendment.
 This was the first presidential election in which residents in Alaska and Hawaii were able to participate, as both had become states in 1959.