Fewer young people are getting tattoos. The number of 20-29 year-olds with tatts has levelled out, and maybe even started falling, ending 15 years of steady growth.
Data on tattooing is sparse and patchy. The latest reliable number for Australia is 15 years old. I was able to squeeze out a time series from a handful of surveys by applying some modelling assumptions. Perhaps I've missed the point of Seeing Like A State, but I've been daydreaming about a tax on body decoration, which would be regressive and stupid as a fiscal policy but would generate precise data to satisfy everyone's curiosity.
Even so, it looks like tattoo prevalence doubled in the 1990s and then plateaued in the 21st century. If you skim the public health literature, you learn that tattoos correlate with risk-seeking behaviour like smoking and multiple sexual partners, and lower SEO status. But the crosstabs reveal that the trend stories in the mid-late 90s were right. Previously only poor people got tattoos, but starting with Generation X, people from every social class do.
I've been thinking about this because a friend introduced me to Just Tattoo Of Us, a reality show where the participants are pairs of close friends. They each choose a tattoo design for each other to receive secretly, then their blindfolds are removed one right after the other. In the episode I watched, one woman received a chastity belt tattooed on her lower abdomen, while her best friend got I LIKE IT IN THE ASS written across her lower back. Fascinating.
The character 文, which in classical Chinese means 'culture', is etymologically a drawing of a person with a tattoo. Over the centuries, the tattoo has been simplified to the dot at the top, and the human has been abstracted into three lines. It illustrates the fact that tattooing is one of the oldest aspects of human civilisation. The very earliest ones were simple dots or random-seeming patterns, which one expert interprets as magical protections, or perhaps decorations.
But this also seems like a useful application of structuralism. We understand the world by imposing structures with arbitrary value in themselves but meanings in relation to each other. We make divisions: between the natural and the social, the raw and the cooked. By drawing a tattoo, we can transform a natural object (a human body) into a cultural one. I think it's the same impulse that leads tech-industry people to put stickers on their laptops.
So I'm left wondering why three quarters of young people don't have a tattoo.
 A YouGov survey of the UK and the US asked people the exact age they were when they first got a tattoo. Both countries' curves were similar, with half of people with tattoos getting it by their early twenties. If you assume that curve is stable over time, then the age-range breakdowns of other surveys can be rescaled and translated back into the past. The surveys I could find were: an Australian survey of health status which included demographic data; and a specific survey of body modification; a US survey of body modification; a repeated US Harris poll of attitudes to tattoos; and the US split of that YouGov survey.
 Try asking your close friends what they'd choose for you if you went on the show. I learned that one person would give me COGITO ERGO SUM across the forehead, so please contact me if you know a good divorce lawyer.
 i.e. that character is a pure pictogram. The large majority of Chinese characters are not pictograms, but rather combinations of simpler elements where half the character represents the sound and half the meaning, and neither has anything much to do with being a drawing of something.