Frequencies for first 10,000 rows of eimageo variable in nhamcsopd2008 dataset :

   if yes, are |
    electronic |
        images |
     returned? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         blank |        309        3.09        3.09
       unknown |      2,323       23.23       26.32
not applicable |      2,711       27.11       53.43
           yes |      3,629       36.29       89.72
            no |      1,028       10.28      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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