Frequencies for planid variable in mmp2019 dataset :

    Plan ID |      Freq.     Percent        Cum.
------------+-----------------------------------
            |          1        0.29        0.29
        001 |        336       97.96       98.25
        002 |          4        1.17       99.42
        005 |          1        0.29       99.71
        006 |          1        0.29      100.00
------------+-----------------------------------
      Total |        343      100.00

by Jean Roth , jroth@nber.org , 15 Feb 2019