79/80 = 98.75%
A value like 98.75% can show up in everyday life when a product is nearly full, a test score is close to perfect, or a service is available almost all the time. It describes something that is just a little short of complete.
To picture 79/80 quickly, imagine 80 equal pieces with 79 shaded and only one left blank. It is very close to 100%, so you can estimate it as about 99%.
One common point of confusion is thinking 98.75% means exactly 99% or 100%. It is close to both, but it is still 1.25 percentage points below 100%.