Frequencies for first 10,000 rows of nationalpdp variable in ma2012 dataset :

   National |
        PDP |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,751       97.51       97.51
          Y |        249        2.49      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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