If God wanted to indicate to us how many are saved, roughly, to give us a sense of what true acceptance of John 3.16,18 is, what would He use to indicate this truth, since obviously not everyone who says they are Christian is?

The new city in the new earth after the millennial-to-come is 1379 x 1379 miles in area on th new earth, with the space above 1379 miles. The walls of the new city are 216 feet high too. All of this is disclosed in Rev. 21.

I think of the size of new city about the size of India or half the size of USA. I can't imagine more than about 1.2 billion souls in this area: the resurrected-saved with their spiritual bodies just like Christ had when He was resurrected.

To determine the savings ration, see here.

You can see by this calculation, that Christ is going to return this century probably, otherwise the savings ratio gets too absurdly low.

Try your own calculations: you will see Christ could not have returned before the 21st century because the savings ratio would have been too high, higher than in the millennium, which makes no sense.

Therefore, Christ will probably return this century especially considering Israel has reclaimed Jerusalem in 1969 and the prophecies of the sixth seal are almost completed (Rev. 6): e.g. man landed on the moon and entered into space to see the darkened eclipsed sun and total red lunar eclipse of the moon: these are the signs of the sun and the moon.

It is soon. Real soon as the nations of the earth will bring a 200 million machine army to fight in the middle east (Rev. 9.16) over oil, and nuclear weapons, and maybe bird flue, will be the cause of killing 1/3 of the people of the earth (Rev. 9.18).

Previous wars in history were over some vital resource.

Then Christ returns to stop it! He returns in Person to step down on the mount of olives, returning just as He left to the clouds, then from the clouds.

Many do not have faith to believe this.