When was 19.2 inch spacing used for rafters and joists?

Ever since engineered framing lumber became common. Traditionally in American construction 16" on-center is common for a lot of framing though roof trusses are often set at 24" in my area. The newer engineered materials like I joists are stronger than standard lumber and have a wide top and bottom so some contractors set them at 19.2" centers because they can use fewer joists which is cheaper for the customer.