Frequencies for first 10,000 rows of arrive variable in nhamcsed2004 dataset :

 mode of arrival |      Freq.     Percent        Cum.
-----------------+-----------------------------------
no box is marked |        283        2.83        2.83
       ambulance |      1,728       17.28       20.11
  public service |        183        1.83       21.94
         walk-in |      7,589       75.89       97.83
         unknown |        217        2.17      100.00
-----------------+-----------------------------------
           Total |     10,000      100.00

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