Frequencies for first 10,000 rows of uld_ruptr variable in natlterr2003 dataset :

  Premature |
 Rupture of |
 Membrane U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        164        1.64        1.64
          2 |      9,810       98.10       99.74
          8 |         23        0.23       99.97
          9 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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