Frequencies for ptype variable in impact2005 dataset :

   Provider |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,979       74.79       74.79
          7 |        165        4.14       78.94
          8 |         39        0.98       79.91
         14 |        215        5.40       85.31
         15 |          7        0.18       85.49
         16 |        485       12.18       97.67
         17 |         87        2.18       99.85
         21 |          3        0.08       99.92
         22 |          3        0.08      100.00
------------+-----------------------------------
      Total |      3,983      100.00

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