I found this quote in a wonderful book called 3 men in a boat. The book was written in 1889 by Jerome K. Jerome, and interestingly it does not seem that much has changed since then.
I knew a young man once, he was a most conscientious fellow and, when he took to fly-fishing, he determined never to exaggerate his hauls by more than twenty-five percent.
“When I have caught forty fish,” said he, “then I will tell people that I have caught fifty, and so on. But I will not lie any more than that, because it is sinful to lie.”