Frequencies for first 10,000 rows of distress variable in natl1991 dataset :

      Fetal |
   distress |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        378        3.78        3.78
          2 |      9,591       95.91       99.69
          8 |          1        0.01       99.70
          9 |         30        0.30      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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