moved from quest since it is general discussion. I also remember at least one previous thread which discussed this topic. 
How many Lucid Dreamers are there in the world?
What about a city or a school?
are you referring to people who can LD naturally? people who work on LDing using techniques? people who will have an LD in their lifetime?
for all those questions, i really have no idea…but i figure clarifying might help people in their answers
People who are already lucid naturally.
My guess is less then 1% to 5% of the world population.
Even from the ancient societies to now.
I doubt there are many that KNOW that there’s a name to be lucid in a dream, but I’m sure there are quite a lot of people that may have experienced this.
But I’m not sure if they will tell you that they have LDs if you ask them; no one want’s to be called crazy 
But who isn’t crazy nowadays? And don’t answer "I’m not crazy!’ (Becouse we all know everyone is crazy) 
It’s hard to tell. There could be hundreds of thousands of practicing LDers, and millions who have LDed at some point.
And i’m not crazy…
ok, yes, Im crazy.
Very hard to say, since many people got LD at least once in their lifetime
My guess would be about 6-7% are active LD’ers and this number changes…
I knew it! Lol. 
Im guessing…
But theres about 7 billion people in the world.
and I would say that 10 million of that 7 billion are natural LDers. and about 1-3 million people practises lucid dreaming.