When did office chairs get their fifth wheel?

Modern swiveling office chairs almost universally have five wheels on five legs, while vintage chairs often have only four. The fifth wheel adds a lot of stability against tipping over; the physics and geometry of this arrangement must have been obvious quite a long time ago. This related question on a sister site shows that the change was in place by the 1980s, as well as naming reasons motivating it.

When did the fifth wheel and leg become normalized in the manufacture of office chairs?

Something went wrong. Wait a moment and try again.