[Paul R.]

Correction, - I ran my sentences together somehow. Should be:

If the birth rate is 1.0 children per woman, then each generation is roughly 1/2 the numbers of the last, and each individual ends up with, on average, two elderly persons to support. If the birth rate is 0.5 children per woman, then each generation is roughly 1/4 the numbers of the last, and each individual ends up with, on average, four elderly persons to support.

[Garth Tater]

You also missed the part where Right_Wing_Madman said:

"When the birth rate is 2.0 (two children per woman), one married couple supports two grandparents."

His number was for a married couple, not per person as you used in your calculations.

R_W_M may be a madman, but he does know his math - and the sad thing is that the math says the Europeans will soon be gone. Much of Asia is heading down that same road at an even faster rate.