Frequencies for ptype variable in impact2003 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
       0.00 |      3,192       73.85       73.85
       7.00 |        202        4.67       78.53
       8.00 |         45        1.04       79.57
      14.00 |        243        5.62       85.19
      16.00 |        553       12.80       97.99
      17.00 |         82        1.90       99.88
      21.00 |          5        0.12      100.00
------------+-----------------------------------
      Total |      4,322      100.00

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