Frequencies for first 10,000 rows of prothr variable in namcs2008 dataset :

 percent of patient care revenue |
              from other sources |      Freq.     Percent        Cum.
---------------------------------+-----------------------------------
                           blank |        435        4.35        4.35
less than or equal to 25 percent |      9,351       93.51       97.86
                   26-50 percent |         83        0.83       98.69
                   51-75 percent |         83        0.83       99.52
            more than 75 percent |         48        0.48      100.00
---------------------------------+-----------------------------------
                           Total |     10,000      100.00

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