In what year, and in what industry, did business process outsourcing first take the form recognized today, rather than only general contracting-out of a business function?

The source article defines BPO and gives an early example (Coca-Cola outsourcing parts of its supply chain) under its Types section, crediting manufacturing firms with originating the practice, but it names no year for that origin and no year for when BPO became a distinct, named business-process category rather than ordinary subcontracting.