Display donations total

I am using paid subscriptions to collect some sponsors' money.
Sponsoring is solely used to cover operational cost of the forum, thus the total available money decreases month by month by a regular amount, plus will be reduced by one offs (e.g. licenses).

As the sponsors are not "too busy" these days I thought about posting the level of remaining donations somewhere in the forum (e,g, footer or header), but have no clue how to do it.
Search function didn't reveal any solution either.

Any idea welcome

Thanks
ac