http://yhoo.it/9K44hN lists the historical price of Dow Jones Industrial index in a table. The 6th column of this table is the volume information. What does the volume listed in this column exactly represent?
For example, consider the following line from this table:
Date | Open | High | Low | Close | Volume Sep 2, 2010 | 10,270.08 | 10,350.98 | 10,211.80 | 10,320.10 | 3,704,210,00
The last number 3,704,210,000 is the volume information. What does it exactly represent?