Frequencies for first 10,000 rows of cord variable in natl1999 dataset :

       Cord |
   prolapse |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         22        0.22        0.22
          2 |      9,978       99.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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