T-SQL (SS2K8) :: Dividing Two Rows Within CASE Statement

I was given the task to come up with a result set based on certain criteria:

Please add one row for each offer code

1) Opt-in rate by offer code: This can be calculated by dividing XXX Inventory with lead / XXX Inventory (A)

The report should read something like below:

Example result set:

Log Date: OfferLetter OfferCode DailyCount

2014-07-20 A XXX Inventory (A) 108
2014-07-20 A XXX Inventory with lead 54
2014-07-20 A XXX Inventory Opt-in Rate: 50%

There are 12 different groupings and OfferLetter A is just one of them.

Below is the code that is written to date:

DECLARE @Start datetime = DATEADD(day, DATEDIFF(day, 0, GETDATE() - 8), 0)
DECLARE @End datetime = DATEADD(day, DATEDIFF(day, 0, GETDATE() - 1) + 1, 0)
DECLARE @Today datetime = DATEADD(day, DATEDIFF(day, 0, GETDATE() - 1), 0);

SELECTDT.OfferCode, DT.OfferCodeDesc
INTO#tempOfferCodes

[Code] ....

The issue I'm having is that the values I need to divide by are in fact, a result set from the CASE statement. It's been a long time since I've done anything like this.