Frequencies for first 10,000 rows of ccs variable in nhamcsopd2007 dataset :

     does this |
  clinic offer |
      cervical |
        cancer |
    screening? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         blank |        412        4.12        4.12
       unknown |         30        0.30        4.42
not applicable |      5,171       51.71       56.13
           yes |      2,857       28.57       84.70
            no |      1,530       15.30      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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