Frequencies for first 10,000 rows of uab_venl30 variable in natl2006 dataset :

   Assisted |
Ventilation |
   < 30 min |
        RFP |
745=f_uab_v |
    enl30 U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        377        3.77        3.77
          2 |      9,483       94.83       98.60
          9 |        140        1.40      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015