Frequencies for ptype variable in impact2001 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
       0.00 |      3,640       73.05       73.05
       7.00 |        176        3.53       76.58
       8.00 |         45        0.90       77.48
      14.00 |        353        7.08       84.57
      16.00 |        703       14.11       98.68
      17.00 |         60        1.20       99.88
      21.00 |          6        0.12      100.00
------------+-----------------------------------
      Total |      4,983      100.00

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