Frequencies for first 10,000 rows of stimula variable in natl2002 dataset :

Stimulation |
   of labor |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,747       17.47       17.47
          2 |      7,947       79.47       96.94
          9 |        306        3.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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