Frequencies for first 10,000 rows of abg variable in nhamcsed2013 dataset :

   Arterial |
blood gases |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,586       95.86       95.86
        Yes |        414        4.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016