Date Table Question

Hi,

I have created a Date table - see picture below:

Now, I would like to add numbers - and I have used the formula I am showing. However, it is a multi-year date table from 2017-2024. So, naturally January 2017 should be #1. However, January 2018, 2019 and so on also get the #1. I would like January 2018 to be #13. 

Is anyone capable of helping with this?