Frequencies for planid variable in mmp2017 dataset :

    Plan ID |      Freq.     Percent        Cum.
------------+-----------------------------------
        001 |        639       99.07       99.07
        002 |          4        0.62       99.69
        005 |          1        0.16       99.84
        006 |          1        0.16      100.00
------------+-----------------------------------
      Total |        645      100.00

by Jean Roth , jroth@nber.org , 6 Dec 2016