How can I make a cell make a percentage based on how much more of "✅" there is in total?

Basically, I have a system showing checkmarks and Xmarks. I want to have a percentage below the cells saying how much ✅ there is, out of the total amount of cells available.

So as you can see, I have items on the left, and the ❌ is a item that...I guess we can say, hasn't been touched. But the ✅s mean the item has been touched. So at the bottom of the cells, I wan't a percentage to say how many ✅s out of the total amount of items. I also want this cell with the percentage to update with a new percentage every time I replace ❌ with ✅.

So if there was 9 ✅s, out of the 19 total items, it would be 47.37%% (right? I'm bad at math idk). But when I replace the next X with a ✅, then it's 10 ✅s out of a total 19 items, so the percentage would "Automatically" update to 52.63%.

How do I go about this? Is there a formula I can use?