"Have confidence: the Free & Clear program has a proven success rate of 25 to 30 percent"
Yes, this was on an actual flyer. Confidence, that 3/4 people will not succeed in this program. Gee, that makes me want to try. Granted, its for a tobacco quitting program, but I don't know that I would boast about this rate by itself, perhaps "25% success rate compared to other programs with only a 10% success rate", now that would sound better... but no, this is standing alone, all by itself. Somebody failed marketing class.
Ignore the raw success rate altogether and go with something like "A 300% higher success rate than _____!" Much more impressive sounding.