Frequencies for first 10,000 rows of prolong variable in natlterr2000 dataset :

  Prolonged |
      labor |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         27        0.27        0.27
          2 |      9,969       99.69       99.96
          9 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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