Frequencies for first 10,000 rows of mddo variable in namcs2014 dataset :

  Type of doctor (MD or DO) |      Freq.     Percent        Cum.
----------------------------+-----------------------------------
  M.D. - Doctor of Medicine |      9,445       94.45       94.45
D.O. - Doctor of Osteopathy |        555        5.55      100.00
----------------------------+-----------------------------------
                      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 27 Mar 2017