86/87 as a percentage is 98.85%. This number tells us that the fraction is almost a whole, missing just a tiny part.
When you see a value this close to 100 %, it means the amount is very nearly complete. In practical terms, if you had 87 items and you already had 86 of them, you’d have covered 98.85% of the total.
People use such percentages to show how close they are to a goal, like finishing a project or reaching a target score. It’s a quick way to see that only a small fraction is left to go.