Frequencies for first 10,000 rows of eimgres variable in namcs2008 dataset :

  practice has |
      computer |
    system for |
       viewing |
       imaging |
      results? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         blank |         25        0.25        0.25
       unknown |        135        1.35        1.60
           yes |      4,777       47.77       49.37
            no |      4,924       49.24       98.61
    turned off |        139        1.39      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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