Frequencies for ptype variable in impact2014 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,788       80.05       80.05
          7 |        207        5.94       85.99
          8 |         31        0.89       86.88
         16 |        331        9.50       96.38
         17 |        124        3.56       99.94
         21 |          1        0.03       99.97
         22 |          1        0.03      100.00
------------+-----------------------------------
      Total |      3,483      100.00

by Jean Roth , jroth@nber.org , 16 Dec 2016