Frequencies for state variable in pdp2016 dataset :

                   State |      Freq.     Percent        Cum.
-------------------------+-----------------------------------
                         |          1        0.08        0.08
                 Alabama |         25        2.01        2.09
                  Alaska |         17        1.37        3.46
          American Samoa |          1        0.08        3.54
                 Arizona |         24        1.93        5.47
                Arkansas |         24        1.93        7.40
              California |         26        2.09        9.49
                Colorado |         24        1.93       11.42
             Connecticut |         24        1.93       13.35
                Delaware |         22        1.77       15.12
                 Florida |         20        1.61       16.73
                 Georgia |         25        2.01       18.74
                    Guam |          2        0.16       18.91
                  Hawaii |         19        1.53       20.43
                   Idaho |         26        2.09       22.53
                Illinois |         26        2.09       24.62
                 Indiana |         26        2.09       26.71
                    Iowa |         24        1.93       28.64
                  Kansas |         23        1.85       30.49
                Kentucky |         26        2.09       32.58
               Louisiana |         23        1.85       34.43
                   Maine |         25        2.01       36.44
                Maryland |         22        1.77       38.21
           Massachusetts |         24        1.93       40.14
                Michigan |         26        2.09       42.24
               Minnesota |         24        1.93       44.17
             Mississippi |         22        1.77       45.94
                Missouri |         26        2.09       48.03
                 Montana |         24        1.93       49.96
                Nebraska |         24        1.93       51.89
                  Nevada |         26        2.09       53.98
           New Hampshire |         25        2.01       55.99
              New Jersey |         23        1.85       57.84
              New Mexico |         25        2.01       59.86
                New York |         20        1.61       61.46
          North Carolina |         24        1.93       63.40
            North Dakota |         24        1.93       65.33
Northern Mariana Islands |          1        0.08       65.41
                    Ohio |         25        2.01       67.42
                Oklahoma |         25        2.01       69.43
                  Oregon |         24        1.93       71.36
            Pennsylvania |         27        2.17       73.53
             Puerto Rico |          6        0.48       74.01
            Rhode Island |         24        1.93       75.95
          South Carolina |         25        2.01       77.96
            South Dakota |         24        1.93       79.89
               Tennessee |         25        2.01       81.90
                   Texas |         26        2.09       83.99
                    Utah |         26        2.09       86.08
                 Vermont |         24        1.93       88.01
          Virgin Islands |          1        0.08       88.09
                Virginia |         26        2.09       90.19
              Washington |         24        1.93       92.12
         Washington D.C. |         22        1.77       93.89
           West Virginia |         27        2.17       96.06
               Wisconsin |         25        2.01       98.07
                 Wyoming |         24        1.93      100.00
-------------------------+-----------------------------------
                   Total |      1,243      100.00

by Jean Roth , jroth@nber.org , 19 Sep 2018