hi, the report Wizard supports only very simple calculations on a column of data. For example, count, sum, average, etc.
make sure the datatype of your column is correct.
Also for summarization, you can use these options.
http://social.microsoft.com/Forums/en-US/crm/thread/69cd9410-7bfe-4b22-afb7-24a4e343baf7Export data to Microsoft Office Excel.
Use this approach when you need Excel features to summarize or aggregate data, or want to use a PivotTable to view your data in different perspectives. This approach is quick, easy, and flexible. If you come up with a spreadsheet that you'll need again,
you can add it to Microsoft Dynamics crm as a report. Each time you open it, the data can dynamically update.Use a default report, or a report someone else created.
Microsoft Dynamics CRM includes many default reports, and may include custom reports set up specifically for your organization. Many of these reports offer filtering, grouping, and sorting options to help you collect and display just the information you
need.Create your own report.
If the security role assigned to your account has permission, creating your own report using the Report wizard is an easy way to get just the information you need. The wizard makes it easy to summarize and display data from two types of records at once.
This approach offers some advantages over exporting data to Excel:
It can create tables and charts that let you click an item to go right to a specific record in Microsoft Dynamics CRM.
You don't need to know how to use Excel. The wizard guides you through selecting what you want in the report and displaying the data in an easy-to-use format.
Data can be grouped by time intervals or by any field, and summarized by sum, average, maximum, minimum, or percentage.
You can select to show just records with the most or least of one criteria, such as the top 10 accounts by revenue, or the 5 products with the fewest associated orders.
Advanced users can also create their own reports that are more complex than possible with the Report Wizard. This is typically done by an experienced report designer, because it requires setting up a report development environment and knowledge of Microsoft
SQL Server Reporting Services. For more information, see the article