Before, I made a simulator of population estimation, and got a result that all Japanese is going to vanish away by A.D. 3222.

It was a simple program that was used both total fertility rate and death rate.

Though I have to input the death rate in my program source file by my hand, this is an interesting process.

For example, the death rate is

One of ten thousand in the 10's

Six of ten thousand in the 20's

One thousand two hundred of ten thousand in the 85's

Two thousand and twenty-five of ten thousand in the 90's

Three thousand and eighty-eight of ten thousand in the 95's

Now I don't have to think that "I still might not to be in next year"

In the near future, I am about to calculate

"The probability to survival is in next year is 90%"

It might interest me, though,

"The probability to death is in this year is 10%"

will make me unhappy.