pig in a python n. especially in demographics, a spike or surge in a statistic measured over time. (source: Double-Tongued Dictionary)
Further reading
A magnificent new book celebrates the richness and diversity of 450 years of written and spoken English in what is now the United States. It’s called The People’s Tongue, and it’s a sumptuous collection of essays, letters, poems...
If you’re ever near a sundial, step closer and look for a message. Many sundials bear haunting, poetic inscriptions about the brevity of life. Plus, language development in toddlers: why and how little ones pick up the exclamation Uh-oh...