Frequencies for first 10,000 rows of uld_distr variable in natl2005 dataset :

      Fetal |
 Distress U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        284        2.84        2.84
          2 |      9,597       95.97       98.81
          9 |        119        1.19      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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