Frequencies for first 10,000 rows of inj_sev variable in person dataset :

     Injury |
   Severity |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,940       19.40       19.40
          1 |        571        5.71       25.11
          2 |      1,317       13.17       38.28
          3 |      1,903       19.03       57.31
          4 |      4,266       42.66       99.97
          9 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016