Frequencies for state variable in pdp2013 dataset :

                   State |      Freq.     Percent        Cum.
-------------------------+-----------------------------------
                 Alabama |         28        2.11        2.11
                  Alaska |         20        1.51        3.61
          American Samoa |          1        0.08        3.69
                 Arizona |         24        1.81        5.50
                Arkansas |         25        1.88        7.38
              California |         27        2.03        9.41
                Colorado |         24        1.81       11.22
             Connecticut |         25        1.88       13.10
                Delaware |         24        1.81       14.91
                 Florida |         29        2.18       17.09
                 Georgia |         25        1.88       18.98
                    Guam |          1        0.08       19.05
                  Hawaii |         18        1.36       20.41
                   Idaho |         27        2.03       22.44
                Illinois |         27        2.03       24.47
                 Indiana |         26        1.96       26.43
                    Iowa |         27        2.03       28.46
                  Kansas |         25        1.88       30.35
                Kentucky |         26        1.96       32.30
               Louisiana |         25        1.88       34.19
                   Maine |         23        1.73       35.92
                Maryland |         24        1.81       37.73
           Massachusetts |         25        1.88       39.61
                Michigan |         28        2.11       41.72
               Minnesota |         27        2.03       43.75
             Mississippi |         24        1.81       45.56
                Missouri |         26        1.96       47.52
                 Montana |         27        2.03       49.55
                Nebraska |         27        2.03       51.58
                  Nevada |         24        1.81       53.39
           New Hampshire |         23        1.73       55.12
              New Jersey |         24        1.81       56.93
              New Mexico |         25        1.88       58.81
                New York |         23        1.73       60.54
          North Carolina |         25        1.88       62.42
            North Dakota |         27        2.03       64.46
Northern Mariana Islands |          1        0.08       64.53
                    Ohio |         28        2.11       66.64
                Oklahoma |         25        1.88       68.52
                  Oregon |         25        1.88       70.41
            Pennsylvania |         33        2.48       72.89
             Puerto Rico |         14        1.05       73.95
            Rhode Island |         25        1.88       75.83
          South Carolina |         26        1.96       77.79
            South Dakota |         27        2.03       79.82
               Tennessee |         28        2.11       81.93
                   Texas |         27        2.03       83.96
                    Utah |         27        2.03       85.99
                 Vermont |         25        1.88       87.88
          Virgin Islands |          1        0.08       87.95
                Virginia |         26        1.96       89.91
              Washington |         25        1.88       91.79
         Washington D.C. |         24        1.81       93.60
           West Virginia |         33        2.48       96.08
               Wisconsin |         25        1.88       97.97
                 Wyoming |         27        2.03      100.00
-------------------------+-----------------------------------
                   Total |      1,328      100.00

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