Frequencies for state variable in mmp2015 dataset :

        State |      Freq.     Percent        Cum.
--------------+-----------------------------------
   California |         16        3.51        3.51
     Illinois |         62       13.60       17.11
Massachusetts |         14        3.07       20.18
         Ohio |         63       13.82       33.99
     Virginia |        301       66.01      100.00
--------------+-----------------------------------
        Total |        456      100.00

by Jean Roth , jroth@nber.org , 14 Apr 2016