Macbook Air Storage

Afternoon Everyone

Quick question i wanted to check what storage space i have left on my macbook air , so apple>about this mac > storage then i get this .

So the question is , it says , I have 83GB free, but the graphic at the bottom paints a different picture , it says I've used 91GB on apps , so either way something is wrong. I very careful about how much i load but this can't be right , in my mind , i should have 83 gigs based on how i have monitored since purchase.

Can anyone shed any light.

Many Thanks Dave M