Frequencies for first 10,000 rows of prothr variable in namcs2007 dataset :

 percent of patient care revenue |
              from other sources |      Freq.     Percent        Cum.
---------------------------------+-----------------------------------
                           blank |        497        4.97        4.97
less than or equal to 25 percent |      9,328       93.28       98.25
                   26-50 percent |        103        1.03       99.28
                   51-75 percent |         42        0.42       99.70
            more than 75 percent |         30        0.30      100.00
---------------------------------+-----------------------------------
                           Total |     10,000      100.00

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