Decades may describe any 10-year period, such as those of a person's life, or refer to specific groupings of calendar years.
Sometimes, only the tens part is mentioned ('60s or sixties, and '70s or seventies), although this may leave it ambiguous as to which century is meant.
[2] Particularly in the 20th century, 0-to-9 decades came to be referred to with associated nicknames, such as the "Roaring Twenties" (1920s), the "Warring Forties" (1940s), and the "Swinging Sixties" (1960s).
A YouGov poll was conducted on December 2, 2019, asking 13,582 adults in the United States, "When do you think the next decade will begin and end?"
Results showed that 64% answered that "the next decade" would begin on January 1, 2020, and end on December 31, 2029 (0-to-9 method); 17% answered that "the next decade" would begin on January 1, 2021, and end on December 31, 2030 (1-to-0 method); 19% replied that they did not know.