idcodea numeric vector, NLS id
agea numeric vector, age at current year
racea numeric vector, race
marrieda numeric vector
never_marrieda numeric vector
gradea numeric vector, current grade completed
collgrada numeric vector, college graduate
southa numeric vector, lives in south
smsaa numeric vector, lives in SMSA
c_citya numeric vector, lives in central city
industrya numeric vector
occupationa numeric vector
uniona numeric vector, union worker
wagea numeric vector, hourly wage
hoursa numeric vector, usual hours worked
ttl_expa numeric vector, total work experience
tenurea numeric vector, job tenure(years)