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

  Elevation |
  in Meters |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |        260        2.60        2.60
          3 |        260        2.60        5.20
          4 |        780        7.80       13.00
          5 |        260        2.60       15.60
          6 |        520        5.20       20.80
          8 |        260        2.60       23.40
          9 |        260        2.60       26.00
         10 |        260        2.60       28.60
         15 |        260        2.60       31.20
         18 |        260        2.60       33.80
         23 |        260        2.60       36.40
         26 |        520        5.20       41.60
         35 |        260        2.60       44.20
         38 |        520        5.20       49.40
         42 |        260        2.60       52.00
         59 |        260        2.60       54.60
         71 |        520        5.20       59.80
         88 |        260        2.60       62.40
         95 |        260        2.60       65.00
        105 |        520        5.20       70.20
        109 |        260        2.60       72.80
        133 |        260        2.60       75.40
        136 |        260        2.60       78.00
        167 |        260        2.60       80.60
        196 |        260        2.60       83.20
        213 |        260        2.60       85.80
        305 |        260        2.60       88.40
        381 |        260        2.60       91.00
        386 |        260        2.60       93.60
        396 |        260        2.60       96.20
        478 |        260        2.60       98.80
        522 |        120        1.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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