Just when I began to grasp exactly how much one million dollars was, the scale changed to billions of dollars.

This spreadsheet shows selected leading U.S. revenue producers by category for the years 2004 through 2007.  For example, Wal*Mart regained the number one position in revenue from ExxonMobil in 2006.  Wal*Mart's sales for 2006 were about $351 billion, up about 11% from $316 billion in 2005.  ExxonMobil only increased sales by about 2.1% over $340 billion in 2005 to about $347 billion in 2006.

Organizations are ranked by 2007 revenues. 

Leading U.S. Businesses by Revenue - 2007

Before anyone starts feeling sorry for ExxonMobil because of their drop in the rankings, consider the profitability of some selected U.S. organizations shown in the following. 

Sales and Profit of Fortune Top 100 Businesses - 2007