By 2025, ......the world would have 11 billion people, double its number today. Another doubling would take only a bit more than 25 years, as the faster- growing segments of the population become a larger proportion of the total. .....in 2076, the human population would have more than doubled again, passing 46 billion. By 2150 there would be 694,213,000,000 of us, a little over 125 times our present population.
http://discovermagazine.com/1992/nov/howmanypeoplecan152