Frequencies for first 10,000 rows of uld_distr variable in natl2003 dataset :

      Fetal |
 Distress U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        270        2.70        2.70
          2 |      8,888       88.88       91.58
          8 |          7        0.07       91.65
          9 |        835        8.35      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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