Frequencies for ptype variable in impact2008 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,759       76.32       76.32
          7 |        194        5.37       81.69
          8 |         35        0.97       82.66
         14 |        150        4.15       86.80
         15 |          8        0.22       87.03
         16 |        367       10.15       97.18
         17 |         99        2.74       99.92
         21 |          3        0.08      100.00
------------+-----------------------------------
      Total |      3,615      100.00

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