Frequencies for first 10,000 rows of on_ruptr variable in natl2013 dataset :

  Premature |
 Rupture of |
   Membrane |
        RFP |
605=f_on_ru |
    pture R |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      8,708       87.08       87.08
          U |        479        4.79       91.87
          Y |        813        8.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015