Frequencies for ptype variable in impact2006 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,901       75.86       75.86
          7 |        178        4.65       80.52
          8 |         34        0.89       81.41
         14 |        174        4.55       85.96
         15 |         13        0.34       86.30
         16 |        427       11.17       97.46
         17 |         93        2.43       99.90
         21 |          3        0.08       99.97
         22 |          1        0.03      100.00
------------+-----------------------------------
      Total |      3,824      100.00

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