Frequencies for first 10,000 rows of board variable in nhamcsed2012 dataset :

        Are |
admitted ED |
   patients |
       ever |
  'boarded' |
   for more |
     than 2 |
   hours in |
  the ED or |
      obser |      Freq.     Percent        Cum.
------------+-----------------------------------
      Blank |        152        1.52        1.52
    Unknown |        400        4.00        5.52
        Yes |      7,251       72.51       78.03
         No |      2,197       21.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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