Symptoms
The RT table in the environment remains large even after the typical Archive, Reorg, and Unload have been ran.
Cause
This could be due to fragmentation of the RT which makes the table larger than it really is. It could be necessary to shrink the reports table to get it back to its original size.
Resolution
Below is the Oracle documentation for reclaiming space in the database:
http://docs.oracle.com/cd/B28359_01/server.111/b28310/tables007.htm#ADMIN11668