The Exact Moment Big Cities Got Too Expensive for Millennials →

The median rent in Los Angeles has been out of the reach of young people since at least the Carter administration. Chicago, by contrast, was affordable for the typical young worker until 2012 [...]. Most millennials could responsibly budget for rent in Boston as recently as 2004 [...]. San Francisco dipped in and out of unaffordable territory for years, until — after roughly a decade of affordability — rents shot ahead of millennial incomes in 2003; they have continued to outpace salaries ever since.

Since this is the percentage of income young people pay in rent, it's impacted both by lower wages and rising rents.