The 'Presentations Data' report currently contains a column 'G' labeled 'Phone Time (Seconds)'. This report may be located under the 'Content' section of the Reporting tab.
This column will reflect the sum of audio recorded through the IVR phone system added to a presentation. This displays in seconds.
Brainshark has sunset tracking the data for this column as of 2018 however.
If you need additional assistance, please contact Support.