By default BitTorrent keep tracks of your (download/upload) activities over the last 31 days.
To clear the history:
- Click on the Options menu > Preferences > Transfer Cap
- Down in the right pane click on the "Reset History" button
This document, titled « BitTorrent - Reset History », is available under the Creative Commons
license. Any copy, reuse, or modification of the content should be sufficiently credited to CCM