Yes, it's a percentage of an IOU, which looks like how interest is a percentage, and the amount is sent into swarm redistribution.
I was thinking the pulses could be triggered on every IOU, from the "tax", and propagate person-to-person, ideally built on something similar to
holochain's ideas. So they would be perpetual, and people could propagate them as long as its beneficial (when they get too small, people probably stop propagating it), and pulses could also converge, so that many small pulses become larger.
It's untested, the original idea from 2012 was that each person gave to lots of people including strangers (tough within the web-of-trust, but still problems with fake accounts), and the latest idea is to do it person-to-person.
The result is similar to demurrage on IOUs, like alexjc's idea here,
https://www.reddit.com/r/CryptoUBI/comments/2qm0nx/my_best_idea_currency_with_demurrage_on_a_trust/The percentage (tax-rate) could be regulated person-to-person, one idea has been that people
set their own tax-rates and inherit what others use, but as a concept a global tax-rate could also be used.