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					Originally Posted by  Alex
					 
				 
				That's true. But we're now in the second decade of the 2000s. Apparently people care more about that one than about the other one. I assume nobody is going to claim that 1990 was part of the '80s. 
			
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 Yes, from a mathematical standpoint I do consider 1990 to have been the last year of the 9th decade of the 20th century.  Just as I consider 2009 to be the 9th year of the 21st century, and thus the 9th year of the 1st decade of that century.
"The 80's" (like any such designation) is a cultural designation, not a calendar one.