Frequencies for first 10,000 rows of f_uld_rupture variable in natl2004 dataset :

  Premature |
 Rupture of |
 Membrane U |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |          7        0.07        0.07
          1 |      9,993       99.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 21 Jan 2016