Yield on Cost
Also called: YOC, yield on original cost
Yield on cost is the current dividend divided by what you originally paid, not by today's price. A stock bought at $20 now paying $2 has a 10% yield on cost even if the current yield is 2.5%. It's a satisfying number and a misleading one for decisions: the money you could free by selling is today's market value, so today's yield is the relevant comparison against alternatives.
Formula
Yield on cost = Current annual dividend ÷ Original purchase price