It's following the logical progression: Gen X, Millennial (Gen Y), Gen Z.
Want to talk about an age group? Say what it is. How dumb can people be? Here, let's walk though it:
"Today, 20-30 year-olds face a variety of economic challenges."
OMG, that was soooo easy! I didn't have to make up or look up a bullshit label! YAY!