Frequencies for first 10,000 rows of stimula variable in natl1995 dataset :

Stimulation |
   of labor |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,190       11.90       11.90
          2 |      8,783       87.83       99.73
          9 |         27        0.27      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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