Frequencies for first 10,000 rows of uld_distr variable in natl2006 dataset :

      Fetal |
   Distress |
        RFP |
725=f_uld_d |
     istr U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        267        2.67        2.67
          2 |      9,601       96.01       98.68
          9 |        132        1.32      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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