Fill down formula error

[jamieson27]

I have tons of monthly data that I am suppose to be calculating the annual CPI increase for, I have =(B25-B13)/B13 to calculate the first december to december increase. Now I have to do this from year 1920-2000 and each year has 1920.1-1920.12 for the months. So I need to have the first cell be the last two points, and the first cell be +12 from the previous cell.

(next year CPI-current year CPI)/Current year CPI is the formula

1914.01 7.2
1914.02 7.2
1914.03 7.2
1914.04 7.1
1914.05 7
1914.06 7.1
1914.07 7
1914.08 7.2
1914.09 7.2
1914.10 7.3
1914.11 7.3
1914.12 7.3

It is sorted like this, and I have set up the formula for the first two years, and I am trying to fill it down, but this does not give me the right increase. Anyone have any ideas how I could do this quicker instead of every year by hand (which would be about 80) Thanks

[shg]

Welcome to the forum.

So I need to have the first cell be the last two points, and the first cell be +12 from the previous cell.

Pardon?

Posting a workbook and explaining in context would help.

[jamieson27]

Thanks for the welcome, that part is extremely hard to explain lol, just trying to tell you how I need it to increase using the formula. Here is the attached workbook, basically the first row is years, second row is the data I'm using M1 and I need to do december to december so 1914.12-1915.12 would be my first two points. Anything else you need?

[shg]

1. Clear everything in column C except the header.

2. In C13, =(B13 - B2) / B2

3. Select cells C2:C13 (all of them), and drag the fill handle down as far as you want. Every 12th cell will contain the formula.

[jamieson27]

Awesome thanks a lot! Saved me a lot of hassle.