That depends on how you configure Teramind, and on the activity level of your users. With the default configuration and normal usage, Teramind should not use more than 10 KB/s - 20 KB/s upstream. You could configure Teramind to run at a reduced frame-rate and color palettes, and that would cut back up to 50% of bandwidth consumption. Teramind is also aware if the connection is poor and jittery, and will dynamically reduce the frame rate accordingly to minimize bandwidth usage.
For more information, check out this article: Teramind Agent specifications and supported platforms.