Where I live in the US, I would say that twenty percent of people between fifteen and forty have visible tattoos, and thiry percent have visible piercings other than the ears. The guys that stretch out their ear lobes with 'plugs' (look like big grommets) are the ones I wonder about the most. On eguy in town has his ear lobes stretched to about three centimeters, when you look through the hollow plug, it frames a biblical verse tattooed on his neck.
Hmmmm.. you want specifics....difficult...
My set of strange piercings would include any male with any piercing, and females with non-ear piercings (sexist, aren't I??) I'd say about one in 10 Aussies would be in there. Tattoos are more prevalent...probably about 1 in 3 or 4 overall. And someone with a strange piercing almost certainly has a tattoo (like 80-90%).
So I was exaggerating a bit above (I'll send you a copy of my poetic license if you wish ;-) But certainly I've seen a lot more of both here than elsewhere in the world, especially among the young.
Now what exactly are you trying to tell us David? If every second person has piercing or tattoos, then I know it does not imply a completely overlapping set, but the odds of you having one or the other is fairly high...
As someone who hates needles in general, the whole piercing fad leaves me bewildered. Since my neck fusion, I find it very inconvient to take antibiotics just to have my teeth cleaned because your body attacks embedded metal when your teeth bacteria gets into your blood stream.
Plus, all kinds of electrical and magnetic fields could light you up if you get too close to the EM fields. So pierce at your own risk. I cannot see any upside to inflicting pain on your body just to make it even more hazardous to work with electronics.
Just my opinion.