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

     Injury |
   Severity |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,015       20.15       20.15
          1 |        557        5.57       25.72
          2 |      1,322       13.22       38.94
          3 |      1,806       18.06       57.00
          4 |      4,293       42.93       99.93
          9 |          7        0.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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