Frequencies for first 10,000 rows of ctunk variable in nhamcsed2008 dataset :

  ct scan - |
   site not |
  specified |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,897       98.97       98.97
          1 |        103        1.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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