To have separate table with a column value that changes annually

Hi All,

I have a tax number that changes annually(May month). The same rate applies for all categories and only changes annually. Is there a way that there could be a separate tax table with it’s value and date applicable  in relation to other table in the calculations. 

For example- the tax was 0.40 from Jan 20- April30 and then on 1st May it changed to 0.53 and this would further be changed on 1st May 2021. Currently, I have a Tax column in my Rates table and then just use it in my DAX measure to calculate annual tax amount. But since it'll change annually is it possible to have a seperate table with date and it's value applicable. I want to minimalize the manual input. 

My Rates table(importing from a excel sheet) has - Date, Category, UnitRate, Tax  columns.

I am using this values to calculate annual tax - 

Any suggestions on how to get around with this?