Frequencies for first 10,000 rows of stimula variable in natlterr1999 dataset :

Stimulation |
   of labor |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,829       18.29       18.29
          2 |      8,168       81.68       99.97
          9 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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