Frequencies for first 10,000 rows of zipcodes variable in servarea2015 dataset :

                              Zip Codes |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                                        |      9,969       99.69       99.69
16666, 16686, 16829, 16845, 16859, 16.. |          6        0.06       99.75
16677, 16801, 16802, 16803, 16804, 16.. |          5        0.05       99.80
16801, 16802, 16803, 16804, 16805, 16.. |          5        0.05       99.85
                           20041, 20598 |          2        0.02       99.87
20120, 20121, 20122, 20124, 20151, 20.. |          1        0.01       99.88
22003, 22009, 22015, 22027, 22031, 22.. |          2        0.02       99.90
             22125, 22191, 22192, 22194 |          2        0.02       99.92
54102, 54104, 54112, 54114, 54139, 54.. |          1        0.01       99.93
54106, 54107, 54111, 54124, 54137, 54.. |          1        0.01       99.94
54106, 54107, 54115, 54130, 54131, 54.. |          1        0.01       99.95
                    76401, 76433, 76446 |          1        0.01       99.96
                           77331, 77371 |          1        0.01       99.97
77340, 77341, 77342, 77343, 77344, 77.. |          1        0.01       99.98
77430, 77431, 77511, 77512, 77515, 77.. |          1        0.01       99.99
             77514, 77560, 77580, 77597 |          1        0.01      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 9 Dec 2017