▁has ▁completed ) ▁have ▁increased . ▁Ex pert ise ▁and ▁skill ▁cert ified ▁through ▁an ▁academic ▁degree ▁ ▁transl ates ▁into ▁increased ▁scarc ity ▁of ▁an ▁individual ' s ▁occup ational ▁qual ification ▁which ▁in ▁turn ▁leads ▁to ▁greater ▁economic ▁re wards . ▁As ▁the ▁United ▁States ▁has ▁developed ▁into ▁a ▁post - indust rial ▁society ▁more ▁and ▁more ▁employ ers ▁require ▁expert ise ▁that ▁they ▁did ▁not ▁a ▁generation ▁ago , ▁while ▁the ▁manufact uring ▁sector ▁which ▁employed ▁many ▁of ▁those ▁lack ing ▁a ▁post - second ary ▁education ▁is ▁decre asing ▁in ▁size . ▁ ▁In ▁the ▁resulting ▁economic ▁job ▁market ▁the ▁income ▁dis cre p ancy ▁between ▁the ▁working ▁class ▁and ▁the ▁professional ▁with ▁the ▁higher ▁academic ▁degrees , ▁ ▁who ▁possess ▁scar ce ▁amounts ▁of ▁cert ified ▁expert ise , ▁may ▁be ▁growing . ▁ ▁House holds ▁in ▁the ▁upper ▁qu int iles ▁are ▁generally ▁home ▁to ▁more , ▁better ▁educated ▁and ▁employed ▁working ▁income ▁ear ners , ▁than ▁those ▁in ▁lower ▁qu int iles . ▁Among ▁those ▁in ▁the ▁upper ▁qu int ile , ▁ 6 2 % ▁of ▁household ers ▁were ▁college ▁gradu ates , ▁ 8 0 % ▁worked ▁full - time ▁and ▁ 7 6 % ▁of ▁households ▁had ▁two ▁or ▁more ▁income ▁ear ners , ▁compared ▁to ▁the ▁national ▁percent ages ▁of ▁ 2 7 %, ▁ 5 8 % ▁and ▁ 4 2 %, ▁respectively . ▁Upper - most ▁sphere ▁US ▁Census ▁Bureau ▁data ▁indicated ▁that ▁occup ational ▁achiev ement ▁and ▁the ▁possession