Frequencies for ptype variable in impact2013 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,624       74.97       74.97
          7 |        185        5.29       80.26
          8 |         32        0.91       81.17
         14 |        195        5.57       86.74
         15 |         18        0.51       87.26
         16 |        326        9.31       96.57
         17 |        118        3.37       99.94
         22 |          2        0.06      100.00
------------+-----------------------------------
      Total |      3,500      100.00

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