The NICKEL.DAT data file has the structure

  Variable                 Columns    Fortran Format
  --------                 -------    ------- ----
  Case ID                    1- 4           I4
  Primary ICD Code           7- 9           I3
  Exposure                  12-15          F4.1
  Date of Birth             18-26          F9.4
  Age first employed        29-36          F8.4
  Age follow-up began       39-46          F8.4
  Age at death or loss      49-56          F8.4

with the fortran format 

          (I4,2X,I3,2X,F4.1,2X,F9.4,3(2X,F8.4)).  

There are 679 records representing the 679 cases
in the nickel study data file NICKEL.DAT 
(the complete data file).