Frequencies for state variable in pdp2015 dataset :

                   State |      Freq.     Percent        Cum.
-------------------------+-----------------------------------
                         |          1        0.07        0.07
                 Alabama |         29        2.00        2.07
                  Alaska |         23        1.58        3.65
          American Samoa |          1        0.07        3.72
                 Arizona |         29        2.00        5.72
                Arkansas |         28        1.93        7.64
              California |         31        2.13        9.78
                Colorado |         29        2.00       11.78
             Connecticut |         26        1.79       13.57
                Delaware |         26        1.79       15.36
                 Florida |         26        1.79       17.15
                 Georgia |         29        2.00       19.15
                    Guam |          2        0.14       19.28
                  Hawaii |         24        1.65       20.94
                   Idaho |         30        2.07       23.00
                Illinois |         32        2.20       25.21
                 Indiana |         30        2.07       27.27
                    Iowa |         29        2.00       29.27
                  Kansas |         28        1.93       31.20
                Kentucky |         30        2.07       33.26
               Louisiana |         27        1.86       35.12
                   Maine |         27        1.86       36.98
                Maryland |         26        1.79       38.77
           Massachusetts |         26        1.79       40.56
                Michigan |         30        2.07       42.63
               Minnesota |         29        2.00       44.63
             Mississippi |         27        1.86       46.49
                Missouri |         30        2.07       48.55
                 Montana |         29        2.00       50.55
                Nebraska |         29        2.00       52.55
                  Nevada |         31        2.13       54.68
           New Hampshire |         27        1.86       56.54
              New Jersey |         28        1.93       58.47
              New Mexico |         30        2.07       60.54
                New York |         24        1.65       62.19
          North Carolina |         28        1.93       64.12
            North Dakota |         29        2.00       66.12
Northern Mariana Islands |          1        0.07       66.18
                    Ohio |         30        2.07       68.25
                Oklahoma |         30        2.07       70.32
                  Oregon |         29        2.00       72.31
            Pennsylvania |         26        1.79       74.10
             Puerto Rico |          6        0.41       74.52
            Rhode Island |         26        1.79       76.31
          South Carolina |         30        2.07       78.37
            South Dakota |         29        2.00       80.37
               Tennessee |         29        2.00       82.37
                   Texas |         31        2.13       84.50
                    Utah |         30        2.07       86.57
                 Vermont |         26        1.79       88.36
          Virgin Islands |          1        0.07       88.43
                Virginia |         30        2.07       90.50
              Washington |         29        2.00       92.49
         Washington D.C. |         26        1.79       94.28
           West Virginia |         26        1.79       96.07
               Wisconsin |         28        1.93       98.00
                 Wyoming |         29        2.00      100.00
-------------------------+-----------------------------------
                   Total |      1,452      100.00

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