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

    AIR BAG |
AVAILABILIT |
          Y |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        743        7.43        7.43
          3 |         54        0.54        7.97
          4 |          4        0.04        8.01
          9 |      9,199       91.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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