An entry(conceptual row) in the 'cGgsnExtCallRateStatsTable'.
There will always be a single entry in this table. The entry
represents set of global call rate statistics at a given
instance of time.
The agent creates an entry in this table when there is a
valid value set to cGgsnExtCallRateInterval. The agent
destroys an entry in this table when the call rate interval
cGgsnExtCallRateInterval is unset.