Frequencies for first 10,000 rows of uld_distr variable in natl2004 dataset :

      Fetal |
 Distress U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        248        2.48        2.48
          2 |      8,778       87.78       90.26
          9 |        974        9.74      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 21 Jan 2016