Times have changed.
Seems like about thirty years ago, Bhutan was this crazy remote country that was closed off from the rest of the world, at least according to the book. But times have changed, of course. In 2005, a census was indeed taken in Bhutan. Furthermore, the 2011 estimate for Bhutan’s population is 708,427, making it 165th in the world in terms of population.
Related to the last fact, Bhutan apparently has less people than Alaska does.