I chased down the wiki citation https://heimat.woergl.at/verschiedenes/freigeld-woergl which appears to be an official museum? Translated source says:

> While unemployment in Austria increased by 19% in the period of the free money campaign, it fell by 16% in Wörgl

The details of words like from/to/by matter a lot, but assuming translation is correct, maybe the confusion here is about absolute vs relative changes.

Guessing the "over 30%" claim comes from the idea that if Worgl was performing normally unemployment would have also increased 19%, instead it fell 16%, i.e. performed 35% better than baseline, assuming it started in a place around average and could have been expected to be average. A different stat than 0% unemployment, but interesting