Frequencies for first 10,000 rows of arrive variable in nhamcsed1999 dataset :

                        mode of arrival |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                 Ambulance (air/ground) |      1,541       15.41       15.41
Public Service (nonambulance, e.g polic |        261        2.61       18.02
                                Walk-in |      7,441       74.41       92.43
                                Unknown |        397        3.97       96.40
                                  Blank |        360        3.60      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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