Frequencies for first 10,000 rows of cord variable in natl1990 dataset :

       Cord |
   prolapse |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         16        0.16        0.16
          2 |      9,918       99.18       99.34
          9 |         66        0.66      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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