Frequencies for first 10,000 rows of dmp variable in nhamcsopd2007 dataset :

      status of patient enrollment in a |
             disease management program |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                                  blank |        191        1.91        1.91
                                unknown |      3,420       34.20       36.11
                         not applicable |      4,625       46.25       82.36
                     currently enrolled |      1,098       10.98       93.34
ordered/advised to enroll at this visit |         80        0.80       94.14
                           not enrolled |        586        5.86      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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