Frequencies for first 10,000 rows of rupture variable in natl1992 dataset :

  Premature |
 rupture of |
   membrane |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        211        2.11        2.11
          2 |      9,753       97.53       99.64
          9 |         36        0.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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