Frequencies for provtype variable in impact1997 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,357       83.39       83.39
          7 |         93        1.78       85.17
          8 |         46        0.88       86.05
         16 |        684       13.09       99.14
         17 |         34        0.65       99.79
         21 |          7        0.13       99.92
         22 |          4        0.08      100.00
------------+-----------------------------------
      Total |      5,225      100.00

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