percentage change from previous cell over a column.

I need some direction. I've tried looking through the forum, but I feel like I'm probably asking the wrong question. I'm relatively comfortable with excel but just moved out of 2007 and into 365. And it's been a couple years since I've had to lean on a formula this heavily.

I have monthly data from 1919 to 2014 for the US Industrial Production Index. That's 1147 data points. I need to find a way to apply a formula for yearly percentage change over the entire column.

So I need cell b2 to =a2/a1, then a value for b3 to =a3/a2 and so on.

First and foremost, does anyone know how to do that? Or can you point me in the right direction?
Secondly is there a term for what I'm trying to do that would make my search a bit more fruitful?

I appreciate any help, thanks.

Have you ever seen a grown man facepalm in public? Thank you. You just cleared a major hurdle for me.