Frequencies for state variable in pdp2012 dataset :

                   State |      Freq.     Percent        Cum.
-------------------------+-----------------------------------
                 Alabama |         32        2.00        2.00
                  Alaska |         25        1.56        3.56
          American Samoa |          1        0.06        3.62
                 Arizona |         30        1.87        5.49
                Arkansas |         30        1.87        7.36
              California |         33        2.06        9.42
                Colorado |         28        1.75       11.17
             Connecticut |         30        1.87       13.04
                Delaware |         31        1.93       14.97
                 Florida |         33        2.06       17.03
                 Georgia |         30        1.87       18.90
                    Guam |          1        0.06       18.96
                  Hawaii |         25        1.56       20.52
                   Idaho |         33        2.06       22.58
                Illinois |         33        2.06       24.64
                 Indiana |         31        1.93       26.58
                    Iowa |         33        2.06       28.63
                  Kansas |         31        1.93       30.57
                Kentucky |         31        1.93       32.50
               Louisiana |         30        1.87       34.37
                   Maine |         28        1.75       36.12
                Maryland |         31        1.93       38.05
           Massachusetts |         30        1.87       39.93
                Michigan |         34        2.12       42.05
               Minnesota |         33        2.06       44.10
             Mississippi |         30        1.87       45.98
                Missouri |         30        1.87       47.85
                 Montana |         33        2.06       49.91
                Nebraska |         33        2.06       51.97
                  Nevada |         29        1.81       53.77
           New Hampshire |         28        1.75       55.52
              New Jersey |         30        1.87       57.39
              New Mexico |         30        1.87       59.26
                New York |         29        1.81       61.07
          North Carolina |         30        1.87       62.94
            North Dakota |         33        2.06       65.00
Northern Mariana Islands |          1        0.06       65.07
                    Ohio |         33        2.06       67.12
                Oklahoma |         30        1.87       69.00
                  Oregon |         30        1.87       70.87
            Pennsylvania |         36        2.25       73.11
             Puerto Rico |         16        1.00       74.11
            Rhode Island |         30        1.87       75.98
          South Carolina |         32        2.00       77.98
            South Dakota |         33        2.06       80.04
               Tennessee |         32        2.00       82.03
                   Texas |         33        2.06       84.09
                    Utah |         33        2.06       86.15
                 Vermont |         30        1.87       88.02
          Virgin Islands |          3        0.19       88.21
                Virginia |         30        1.87       90.08
              Washington |         30        1.87       91.95
         Washington D.C. |         31        1.93       93.89
           West Virginia |         36        2.25       96.13
               Wisconsin |         29        1.81       97.94
                 Wyoming |         33        2.06      100.00
-------------------------+-----------------------------------
                   Total |      1,603      100.00

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