Frequencies for first 10,000 rows of arrive variable in nhamcsed2003 dataset :

 mode of arrival |      Freq.     Percent        Cum.
-----------------+-----------------------------------
no box is marked |        227        2.27        2.27
       ambulance |      1,524       15.24       17.51
  public service |        158        1.58       19.09
         walk-in |      7,794       77.94       97.03
         unknown |        297        2.97      100.00
-----------------+-----------------------------------
           Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016