Frequencies for first 10,000 rows of left variable in nhamcsed2006 dataset :

       left |
    without |
 being seen |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,822       98.22       98.22
        yes |        178        1.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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