Reports show many users, especially with broadband: Wi-Fi networks were added in 2 million homes in the last two years or so, and a quarter of all broadband subscribers have wireless networks. (Broadband adoption just ratcheted up in the last year significantly, too, although analysts think that the curve will become shallow given the lack of broadband support for many users who want it outside of urban areas.)
The report apparently also indicates the Wi-Fi has driven the growth of home networks. No one wants to run wires, that's clear. No one even wants to build their own cables any more: it's too hard to get the high-speed quality with the reduced wiggle room in faster Ethernet.