Are there any reliable statistical numbers about the practice of martial arts worldwide? I'm very curious about the how widespread such practices are, where they are most popular, what styles & schools are practiced by region, and the like. I'm not sure where to find any reliable data, especially impartial unbiased stuff.
What you're looking for is martial arts demographics. And you want world-wide demographics. Both of which seem kind of hard to come by.
The demographics you're looking for might be along the lines of: how many people are there doing martial arts, what percentage of the population is currently practicing one or has ever practiced one, average time spent per week, average time spent before quitting, which martial arts are most popular, average age of participants, average income of participants, etc.
Most demographic polls are conducted by polling organizations that need to be paid for their work. Individual martial arts schools don't make enough money to do this. And they generally aren't going to be interested in martial arts in the broader sense, either.
Some sports and martial arts related magazines and journals have been known to do polling from time to time. For example, here's one on the subject of MMA viewership.
So you might gather a list of magazines and journals and ask them if they have anything that might interest you.
If you search, you might find more. Those just came up in a quick Google search.
Keep in mind there's a difference between an online poll and a professional poll. Professional polls are done by organizations that only poll for a living. They understand how to ask the questions in such a way as to not bias the results. They know how to sample the population so that it takes all ages, all professions, all economic and ethnic backgrounds into consideration.
Whereas, online polling and surveys are automatically biased towards people who are spending time on their computers. It's a certain type of person, perhaps not representative of martial arts practitioners as a whole.
Online polling and surveys often don't ask the right questions or in the right way. And they may not be able to prevent multiple poll results from the same person for the same poll. And their sample size itself may be too small.
I mention that, because there are many online polls and surveys about martial arts. And they're generally pretty low quality.
None of these so far offer the kind of broad, world-wide data you're looking for. I think that kind of thing would be one or two orders of magnitude more rare. Nothing comes to mind.
Hope that helps.
I do not believe so.
I know of no such data being available world wide, nor would I trust any such. Mostly because even something as "number of people insured" is not precise enough. Also, some schools/styles would heavily object being lumped together because ego.
There is some hope…
You could look per style/school and country by looking and trawling through data on parent organisations home pages. Although, this would be error prone and hard.
For example, in the UK, Aikido is represented by the British Aikido Board so all Aikido school/styles are represented there. All, but for the BAA which has quit for political reasons1. Still, between those two you should be able to find out how many people practice.
Aikiweb did run a poll several years back as to the style everyone was practising. I cannot find the results. So, that might be a good way to get a sample. The statistical value of such poll might be negligible.
1: Remember, Aikido is the way of harmony⸮