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

Extrication |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,352       93.52       93.52
          1 |        526        5.26       98.78
          9 |        122        1.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016