Frequencies for first 10,000 rows of vdatefl variable in nhamcsopd1993 dataset :

  was visit |
       date |
   imputed? |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,979       99.79       99.79
          1 |         21        0.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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