Frequencies for pton_rat variable in parkwork dataset :

 Ton Rating |      Freq.     Percent        Cum.
------------+-----------------------------------
            |        784       78.24       78.24
          B |        149       14.87       93.11
         BD |          1        0.10       93.21
          C |         37        3.69       96.91
         CD |          1        0.10       97.01
          D |         27        2.69       99.70
         DG |          1        0.10       99.80
          E |          1        0.10       99.90
          P |          1        0.10      100.00
------------+-----------------------------------
      Total |      1,002      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016