Frequencies for first 10,000 rows of uld_ruptr variable in natl2005 dataset :

  Premature |
 Rupture of |
 Membrane U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        374        3.74        3.74
          2 |      9,507       95.07       98.81
          9 |        119        1.19      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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