Frequencies for first 10,000 rows of ab_aven6 variable in natl2013 dataset :

   Assisted |
Ventilation |
 >6 hrs RFP |
629=f_ab_ve |
      nt6 R |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,597       95.97       95.97
          U |        310        3.10       99.07
          Y |         93        0.93      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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