American Generation Fast Facts

(CNN)Here's a look at six generations of Americans in the 20th century: the Greatest Generation (or GI Generation), the Silent Generation, baby boomers, Generation X, millennials and Generation Z.

In order to examine economic trends and social changes over time, demographers compare groupings of people bracketed by birth year. There are sometimes variations in the birth year that begins or ends a generation, depending on the source. The groupings below are based on studies by the US Census, Pew Research and demographers Neil Howe and William Strauss.

The Greatest Generation (or GI Generation)

Born in 1924 or earlier.
Tom Brokaw coined the term the Greatest Generation as a tribute to Americans who lived through the Great Depression and then fought in WWII. His 1998 bestselling book, "The Greatest Generation," popularized the term.
John F. Kennedy, born in 1917, was the first member of the Greatest Generation to become president. Lyndon B. Johnson, Richard M. Nixon, Gerald R. Ford, Ronald Reagan, Jimmy Carter, and George H.W. Bush were also born between 1901 and 1924.

The Silent Generation

Born 1925-1945 (Sometimes listed as 1925-1942).
A 1951 essay in Time magazine dubbed the people in this age group the "Silent Generation" because they were more cautious than their parents. "By comparison with the 'Flaming Youth' of their fathers & mothers, today's younger generation is a still, small flame."
The Silent Generation helped shape 20th century pop culture, with pioneering rock musicians, iconic filmmakers, television legends, beat poets, gonzo journalists and groundbreaking political satirists.
President Joe Biden is the first member of the silent generation to serve as president.

Baby Boomers

Born 1946-1964 (Sometimes listed as 1943-1964)
Baby boomers were named for an uptick in the post-WWII birth rate.
At the end of 1946, the first year of the baby boom, there were approximately 2.4 million baby boomers. In 1964, the last year of the baby boom, there were nearly 72.5 million baby boomers. The population peaked in 1999, with 78.8 million baby boomers, including people who immigrated to the United States and were born between 1946 and 1964.
Bill Clinton was the first baby boomer to serve as president. George W. Bush, Barack Obama, and Donald Trump are also baby boomers.

Generation X

Born 1965-1980 (Sometimes listed as 1965-1979)
"Class X" was the name of a chapter in a 1983 book, "Class: A Guide Through the American Status System," by historian Paul Fussell. Novelist Douglas Coupland used the term as the title of his first book, "Generation X: Tales for An Accelerated Culture," published in 1991.
No members of Generation X have served as president.
In the 2016 presidential election, Generation X-ers and millennials made up more than half of the electorate, according to Pew. For the first time in decades, younger voters outnumbered older voters, albeit by a slight margin. Millennials and Generation-X-ers (age 18-51), cast 69.6 million votes, compared with 67.9 million votes cast by Baby Boomers and older voters (age 52 and up).