When was the game franchise started?
The game started on the 20th of September, 1984, and it was a very advanced game for the day. It featured only one solar system, but the system itself was huge.
Frontier then released a few versions of the game, then Elite: Dangerous was released in 2014, and it took the world by storm.

How popular is the game?
Estimates put the number of players who own the game to be somewhere around 3-4 million people, yet the all time record for how many people online at the same time is only 18,039. And only 3.5% of the playable game is explored. It would take 150,895 years to explore all of it. There is an average of 17,585 systems discovered everyday, thats 732 per hour, and 12 per minute. There are 400 billion systems to explore as well, so this is going to take a while.

Each of those lights in the image below are explorable.