Maintain Historical Data For Prior Months

I am having a little issue when I bring in monthly data in a report but want to maintain the values for the prior months. In the workbook attached, the data for the current month in range B2:B6 gets wiped every new month to enter the new month numbers in.

Now I have sumif formulas to calculate the numbers for the current month but I would like to keep the data for the prior months. I know I could paste values every month before I enter the new month data but in my actual workbook, there are many more sections spread apart. I was curious to know if there is a macro or any other way to do this.

Thanks