Frequencies for first 10,000 rows of usaf variable in nsrd dataset :

     United |
 States Air |
      Force |
     (USAF) |
    Station |
Identificat |
 ion Number |      Freq.     Percent        Cum.
------------+-----------------------------------
     700260 |        260        2.60        2.60
     700637 |        260        2.60        5.20
     701043 |        260        2.60        7.80
     701195 |        260        2.60       10.40
     701330 |        260        2.60       13.00
     701718 |        260        2.60       15.60
     701740 |        260        2.60       18.20
     701780 |        260        2.60       20.80
     701940 |        260        2.60       23.40
     702000 |        260        2.60       26.00
     702005 |        260        2.60       28.60
     702040 |        260        2.60       31.20
     702070 |        260        2.60       33.80
     702084 |        260        2.60       36.40
     702185 |        260        2.60       39.00
     702186 |        260        2.60       41.60
     702190 |        260        2.60       44.20
     702310 |        260        2.60       46.80
     702320 |        260        2.60       49.40
     702460 |        260        2.60       52.00
     702495 |        260        2.60       54.60
     702510 |        260        2.60       57.20
     702590 |        260        2.60       59.80
     702600 |        260        2.60       62.40
     702606 |        260        2.60       65.00
     702607 |        260        2.60       67.60
     702610 |        260        2.60       70.20
     702647 |        260        2.60       72.80
     702650 |        260        2.60       75.40
     702670 |        260        2.60       78.00
     702710 |        260        2.60       80.60
     702720 |        260        2.60       83.20
     702730 |        260        2.60       85.80
     702735 |        260        2.60       88.40
     702740 |        260        2.60       91.00
     702756 |        260        2.60       93.60
     702757 |        260        2.60       96.20
     702770 |        260        2.60       98.80
     702910 |        120        1.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 15 Jun 2016