https://www.theregister.co.uk/2019/09/03/eben_upton_pi_store/

Interview The Register popped into the Raspberry Pi Foundation's retail outlet in Cambridge to chat with founder Eben Upton about power, sales and occupying the family television.

It is less than eight years since the first Pi fell into the hands of excited users. Sales of the diminutive computer, produced by a Sony facility in Wales, have hit around half a million units a month. The most recent incarnation, the Pi 4, accounted for half a million on its own since its June launch.