120 per 100,000 includes significant digits. 0.12% could be anywhere from 120-124 per 100,000. You'd really want 0.120%, but that's confusing for different reasons.
Worse would be 1,000 per 100,000, which is 1% but there's no way to tell that it's not rounded or truncated.
Worse would be 1,000 per 100,000, which is 1% but there's no way to tell that it's not rounded or truncated.