Frequencies for first 10,000 rows of prolong variable in natl1993 dataset :

  Prolonged |
      labor |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         53        0.53        0.53
          2 |      9,923       99.23       99.76
          9 |         24        0.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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