Vaidy points out a small bug in the stored procedure for the GP2010 – Sales Charts & KPIs – Top Items By Sale Amount He also provides a fix.
Sales Charts & KPIs – Top Items By Sale Amount – Stored Procedure Bug
Install, Upgrade & AdminSales, Purchasing & InventoryReporting & BIGP 2010
Archived post from 2010. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.