Frequencies for qualred variable in impact2017 dataset :

      Proxy |
    Quality |
  Reduction |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      3,279       96.19       96.19
          1 |        130        3.81      100.00
------------+-----------------------------------
      Total |      3,409      100.00

by Jean Roth , jroth@nber.org , 30 Aug 2017