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

     does this |
  clinic offer |
      cervical |
        cancer |
    screening? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         blank |        424        4.24        4.24
not applicable |      4,886       48.86       53.10
           yes |      2,246       22.46       75.56
            no |      2,444       24.44      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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