Since their introduction in 1978, Lego's minifigs have, um, reproduced at a rapid rate. In fact, the toymaker has been making the little fellas at such a pace that they'll outnumber humans by 2019.
As of 2006, there were four billion minifigs in the world; projecting forward both human and Lego populations suggests that tiny plastic men will outnumber us by 2019. Imagine that: a world where there are more minifigs than fellow homo sapiens. That's our kind of world. [XKCD]