Lots of retirees, especially from US Patent and Trade. Some folks with vision or mobility impairment who like being above the underground.
When I was in bidness school, the word "yuppie" had not yet become generally accepted. The term my marketing prof used was "Y.P." He said they were the coke sniffers in the London Fog ads. The word "yuppie" kind of became common lingo around 1984 in connection with Gary Hart's campaign. Young Urban Professional. The alternative was "Yump:" young upwardly-mobile professional.