Need help with Excel formula!!

[jlhoops33]

Hey squall01 and soybean.  Thanks to both of you for helping me out on this one.  You're both a great help!! I REALLY appreciate it.  Been struggling w/this for 4 days now!!  Anyway, first off, I am using Excel 02 version.  Below I've copied some data from the first two columns of the spreadsheet I'm working on.  Soybean, what you've mentioned is giving me a good idea, but I'm not quite there.  When I said time periods, I should have been more specific.  I meant periods of the year, so the first column covers Jan., 2nd column, Feb.  I need Feb column to show either yellow for a 10% or below difference and red for above 10% difference.  I'm not sure if I need to write and actual formula for this or if I can select an option from the dropdown list in the conditional formatting box.

100.00%   99.34%
97.06%   99.59%
100.00%   98.61%
100.00%   98.97%
98.11%   99.13%

Rather than start another query, thought I'd ask this as well while I've got your attention.  I am putting together a column chart (I'm basically charting Feb percentages above) and want to add a goal line (not a trendline) across the top of 95%.  So far, the closest I've been able to come is to add a line chart of 95% and have it show up that way, but this is a kind of "wing it" solution.  I'd like to be able to know how to to produce an actual goal line.  Been doing some research on the internet, but the instructions are so confusing, I've kind of given up on that.  If there's anyway you could help me on this as well, I would greatly appreciate it.  Thanks alot guys!! 

[soybean]

I should have been more specific.  I meant periods of the year, so the first column covers Jan., 2nd column, Feb.  I need Feb column to show either yellow for a 10% or below difference and red for above 10% difference.  I'm not sure if I need to write and actual formula for this or if I can select an option from the dropdown list in the conditional formatting box.

Regardless of whether the cells contain data for days, weeks, or months, the principle is the same.  You need one or two columns to calculate the change.  In the example-image I posted earlier, I used two columns; that can be consolidated into one column.  So, column C could be used to calculate the percentage change between whatever is represented in A1 and B1.  Conditional formatting would be applied to Column B, then, to accomplish your objective.  If you don't want to see the column(s) used to calculate the change, then just hide it/them.

Here are two images to illustrate a three column layout and the conditional formatting panel for B1: