Frequencies for first 10,000 rows of nnochrge variable in namcs2011 dataset :

       Type of |
       payment |
 accepted from |
 new patients: |
     No charge |      Freq.     Percent        Cum.
---------------+-----------------------------------
         Blank |        221        2.21        2.21
       Unknown |        919        9.19       11.40
Not applicable |        583        5.83       17.23
           Yes |      3,284       32.84       50.07
            No |      4,993       49.93      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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