Frequencies for provtype variable in impact1995 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,444       82.96       82.96
          7 |        153        2.86       85.81
          8 |         48        0.90       86.71
         16 |        655       12.23       98.94
         17 |         57        1.06      100.00
------------+-----------------------------------
      Total |      5,357      100.00

by Jean Roth , jroth@nber.org , 17 Mar 2016