Running monthly rate of return for investment account.

I'm a rookie at making financial formulas on Excel 2007 so I need some help. I have made an investment worksheet to keep track of my annual rate of return each month on each account as I enter the monthly totals. I have a cash entry for each end of month statement of the year for each account. So for instance let's say I have all the end of month totals for each account listed for the year up to September 2011. I would like to know what my rate of return is thus far for the year to the end of September. As I add another month total I want the rate of return to change to demonstrate that change. Any help will be appreciated.

Originally Posted by khamilton

If you could attach an example it will get you better help.

Thank you for your reply. Attached you will find the spreadsheet I am trying to design as a .PDF file in Excel 2007. The amounts I am interested in correcting are the ANNUAL% Rate which is the last column. The formulas I am presently using on that spreadsheet are incorrect. However the amounts used in each respective formula are the beginning of the year amounts in each account. If you can help me with the first Function formula I can do the rest....thanks in advance....