In towns like mine, however, 40,000 people share the same zip code with the hospital. I'm sure there are quite a few more town like mine throughout the US.
US pop in 2000: 280,000,000 —
US births in 2000: 4,000,000 —
US births per day: 10,958 —
Fraction of US pop that 40,000 represents: 0.0001428 —
Number of births per day for the 40,000: 1.56
That seems inline with the conclusion of the paper. See any mistakes?