I don't have the source handy, but I remember reading that during his lifetime, Euler was responsible for one third of the entire world's output of new work in the Mathematical Sciences (Maths, Physics and Optics I guess).<p>ONE THIRD!<p>(I think it was from this book: <a href="http://www.amazon.com/Journey-through-Genius-Theorems-Mathematics/dp/014014739X/ref=pd_bxgy_b_img_b" rel="nofollow">http://www.amazon.com/Journey-through-Genius-Theorems-Mathem...</a>)