JT -
If you mean that baptism is down to one third of the goal, i.e. three instead of nine, then there has been about a 67% reduction. The construction "three times fewer" is also acceptable to express one third as many. The expression "300% drop" - or any decrease greater than 100% - is not possible when something expresses only magnitude. I once saw a mattress ad touting "300% less" dust mites. Of course, 100% less than any number would be zero dust mites, which is ideal, but they really meant one third as many, or three times less. If you jumped from 5,000 dust mites to -10,000 dust mites, a 300% reduction, the question would be what is a negative dust mite? And jokes could follow.
Of course if instead of nine being baptized, three are baptized and twenty-one announce their disassociation at the same assembly, then you would have a net loss of eighteen, or a 300% drop in the increase!
BluesBrother: Heard about 1 only at Buckingham, PA within the last couple years.