This mostly confirms that browser statistics vary by region, audience, sites sampled, etc.
That being said, I'd guess if we sampled Facebook and Google (+ regionally strong competitors, e.g. Baidu) we could get a quite accurate sample of the general web population ;-)
I'm wondering what the demographics of wikipedia is though - I'd not be surprised if it's biased towards students and tech people. I know for sure the rest of my family does in no way visit wikipedia as much as me and my co-workers.
This confirms is that browser statistics are rubbish!