Frequencies for first 10,000 rows of cord variable in natl1996 dataset :

       Cord |
   prolapse |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         33        0.33        0.33
          2 |      9,921       99.21       99.54
          9 |         46        0.46      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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