A month ago I began to participate in StackOverflow process. So I was interested to collect some statistics data and find where am I in this game. StackOverflow has a good API with limits for 300 requests/days for anonymous user and 10 000 requests/day for authorized. I created a simple bot on python, collected data to MongoDb and built these charts. With 10 000 requests and page size 100 I got users from highest reputation (524k) to 269. So I built these charts starting from reputation of 300.
The number of users with reputation > 300 is 96 654. And total number of users is about 1 375 000. So the percent of active users is about 7%.
Then, if you look at the users with the filled location and being in my primary countries - Russia, France.
And here there are the users with non empty age.
Finally I built chart by tags for users from Russia at the age range 30-35. There are only 170 such users.