Use your two Totals queries as data sources for a new Query to be used as
the RecordSource of your Report. Join the two Totals Queries on Month. Lay
out the Report something like
Month Sales_for_2005 Sales_for_2006 Percent_Difference
You can calculate the percent difference either in the report, as a
Calculated Control, or in the Query, as a Calculated Field.
Chances are, you will want to use Report Sorting and Grouping to sort the
records by month number, but display month name.
If my description is too cryptic, post back with questions and someone
(maybe even I) will try to clarify.
Larry Linson
Microsoft Access MVP