Frequencies for first 10,000 rows of rupture variable in natl1994 dataset :

  Premature |
 rupture of |
   membrane |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        217        2.17        2.17
          2 |      9,744       97.44       99.61
          9 |         39        0.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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