Frequencies for first 10,000 rows of distress variable in natl1990 dataset :

      Fetal |
   distress |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        382        3.82        3.82
          2 |      9,550       95.50       99.32
          8 |          2        0.02       99.34
          9 |         66        0.66      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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