Frequencies for first 10,000 rows of stimula variable in natl1994 dataset :

Stimulation |
   of labor |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        994        9.94        9.94
          2 |      8,989       89.89       99.83
          9 |         17        0.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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