Frequencies for first 10,000 rows of senbefl variable in namcs1993 dataset :

   was `was |
    patient |
       seen |
   before?` |
   imputed? |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,779       97.79       97.79
          1 |        221        2.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016