More on counting people

Just over a year ago I [wrote about]( Anderson Cooper’s description of America’s growing population. Seems it’s about time for me to do sort of the same thing, only with an ad I saw while over in Chicago for the annual meeting of [my professional organization]( On one of the L trains there was an advertisement for a new book, [The Chicago “L”]( The ad read something like,

> Make a connection to the over 10 billion riders of the Chicago “L”

That was surprising. I thought the current population of the earth was around 6 billion! Anyway, it’s quite clear what is meant, namely that over 10 billion rides have been taken since the opening of the L in 1892, no doubt many involving repeat customers. Fair enough – but do different rides by the same individual require making a new connection with them for each new ride? Sure, some days the trip is special, but whatever connection this book lets me create with, say, Janice Smith going to work on June 3rd, 1985, will probably also work for her going to work on June 4th. Just a guess, of course.

Similarly strange is what is apparently on the blurb (from Amazon):

> More than 10 billion people have ridden the “L,” which now carries half a million people a day over 222 miles of track.

Now, I’d like to claim that more than one thousand people read this blog, but somehow I think I would get called on it…

One interesting thing that came out of this was a little research I did into estimations not of the world’s current population, but of the sum total of humans who’ve ever lived. [One estimate]( puts it at just over 100 billion. More than I would have guessed. And according to the same source, about 11 billion people were alive between 1900 and 2002. So hey, _theoretically_ (maybe?) it’s possible that 10 billion individuals have ridden on the L.