Zillow reported (here) in December that working age adults in 2016 were living in doubled-up households at a rate of 30% compared with 21% in 2005.
That works out to roughly 32 million in 2005 at the 21% rate vs. 50 million in 2016 at the 30% rate, using the Working Age Population data from FRED.
Had the rate remained 21% in 2016, just 35 million would be living doubled-up instead of 50 million.
That's 15 million more adults who can't afford to buy, and can't even afford to rent, thanks to the feckless performances of George W. Bush and Barack H. Obama.
h/t Jeffrey Snider, Alhambra Investments