Im a little confused what this question is asking, but the number in billions is simply 89.61416 if the original number is in thousands! Hope that helps and if that was not what you were looking for, let me know. :)
It is estimated that the population of the world reached one billion for the first time in 1804. It was another 123 years before it reached two billion in 1927, but it took only 33 years to rise by another billion people, reaching three billion in 1960.
