Frequencies for first 10,000 rows of nselfpay variable in namcs2006 dataset :

       for new |
     patients, |
     physician |
      accepts: |
  self-payment |      Freq.     Percent        Cum.
---------------+-----------------------------------
         blank |        163        1.63        1.63
           yes |      8,593       85.93       87.56
            no |        472        4.72       92.28
       unknown |        165        1.65       93.93
not applicable |        607        6.07      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

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