Frequencies for state variable in pdp2017 dataset :

                   State |      Freq.     Percent        Cum.
-------------------------+-----------------------------------
                         |          1        0.10        0.10
                 Alabama |         22        2.14        2.23
                  Alaska |         16        1.55        3.79
          American Samoa |          1        0.10        3.88
                 Arizona |         20        1.94        5.83
                Arkansas |         20        1.94        7.77
              California |         22        2.14        9.90
                Colorado |         21        2.04       11.94
             Connecticut |         19        1.84       13.79
                Delaware |         18        1.75       15.53
                 Florida |         18        1.75       17.28
                 Georgia |         21        2.04       19.32
                    Guam |          2        0.19       19.51
                  Hawaii |         17        1.65       21.17
                   Idaho |         22        2.14       23.30
                Illinois |         21        2.04       25.34
                 Indiana |         21        2.04       27.38
                    Iowa |         20        1.94       29.32
                  Kansas |         20        1.94       31.26
                Kentucky |         21        2.04       33.30
               Louisiana |         18        1.75       35.05
                   Maine |         21        2.04       37.09
                Maryland |         18        1.75       38.83
           Massachusetts |         19        1.84       40.68
                Michigan |         21        2.04       42.72
               Minnesota |         20        1.94       44.66
             Mississippi |         17        1.65       46.31
                Missouri |         21        2.04       48.35
                 Montana |         20        1.94       50.29
                Nebraska |         20        1.94       52.23
                  Nevada |         21        2.04       54.27
           New Hampshire |         21        2.04       56.31
              New Jersey |         19        1.84       58.16
              New Mexico |         21        2.04       60.19
                New York |         17        1.65       61.84
          North Carolina |         20        1.94       63.79
            North Dakota |         20        1.94       65.73
Northern Mariana Islands |          1        0.10       65.83
                    Ohio |         20        1.94       67.77
                Oklahoma |         20        1.94       69.71
                  Oregon |         19        1.84       71.55
            Pennsylvania |         22        2.14       73.69
             Puerto Rico |          6        0.58       74.27
            Rhode Island |         19        1.84       76.12
          South Carolina |         19        1.84       77.96
            South Dakota |         20        1.94       79.90
               Tennessee |         22        2.14       82.04
                   Texas |         21        2.04       84.08
                    Utah |         22        2.14       86.21
                 Vermont |         19        1.84       88.06
          Virgin Islands |          1        0.10       88.16
                Virginia |         21        2.04       90.19
              Washington |         19        1.84       92.04
         Washington D.C. |         18        1.75       93.79
           West Virginia |         22        2.14       95.92
               Wisconsin |         22        2.14       98.06
                 Wyoming |         20        1.94      100.00
-------------------------+-----------------------------------
                   Total |      1,030      100.00

by Jean Roth , jroth@nber.org , 6 Dec 2016