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

     injury |
   severity |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,454       24.54       24.54
          1 |        736        7.36       31.90
          2 |      1,155       11.55       43.45
          3 |      1,196       11.96       55.41
          4 |      4,319       43.19       98.60
          5 |         17        0.17       98.77
          9 |        123        1.23      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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