Frequencies for first 10,000 rows of vyear2 variable in nhamcsed1996 dataset :

    year of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
         95 |        239        2.39        2.39
         96 |      9,761       97.61      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016