American households in different income quintiles differ in predictable ways:
Mean number of earners per household. On average, there are significantly more income earners per household in the top income quintile households (1.98) than earners per household in the lowest-income households (0.41). It can also be seen that the average number of earners increases for each higher income quintile, demonstrating that one of the main factors in explaining differences in income among U.S. households is the number of earners per household. Also, the unadjusted ratio of average income for the highest to lowest quintile of 15.9 times ($185,206 to $11,651), falls to a ratio of only 3.3 times when comparing “income per earner” of the two quintiles: $93,538 for the top fifth to $28,417 for the bottom fifth.
Share of households with no earners. Sixty-three percent of U.S. households in the bottom fifth of Americans by income had no earners for the entire year in 2013. In contrast, only 3.1% of the households in the top fifth had no earners in 2013, providing more evidence of the strong relationship between household income and income earners per household.
Marital status of householders. Married-couple households represent a much greater share of the top income quintile (76.8%) than for the bottom income quintile (16%), and single-parent or single households represented a much greater share of the bottom one-fifth of households (84.0%) than for the top 20% (23.2%). Like for the average number of earners per household, the share of married-couple households also increases for each higher income quintile, from 16% (lowest quintile) to 35% to 50% (middle quintile) to 64% to 77% (highest quintile).
Age of householders. More than 7 out of every 10 households (71.9%) in the top income quintile included individuals in their prime earning years between the ages of 35-64, compared to fewer than half (43.9%) of household members in the bottom fifth who were in that prime earning age group last year. The share of householders in the prime earning age group of 35-64 year olds increases with each higher income quintile.
Compared to members of the top income quintile of households by income, household members in the bottom income quintile were 1.4 times more likely (21.8% vs. 15.8%) to be in the youngest age group (under 35 years), and almost three times more likely (34.2% vs. 12.3%) to be in the oldest age group (65 years and over).
By average age, the highest income group is the youngest (48.8 years) and the lowest income group is the oldest (54.4 years).
Work status of householders. Almost five times as many top quintile households included at least one adult who was working full-time in 2013 (78.8%) compared to the bottom income quintile (only 16.1%), and more than five times as many households in the bottom quintile included adults who did not work at all (69.4%) compared to top quintile households whose family members did not work (12.4%). The share of householders working full-time increases at each higher income quintile (16.1% to 43.9% to 60.4% to 70.7% o 78.8%).
Education of householders. Family members of households in the top fifth by income were almost five times more likely to have a college degree (64.6%) than members of households in the bottom income quintile (only 13.5%). In contrast, householders in the lowest income quintile were 15 times more likely than those in the top income quintile to have less than a high school degree in 2013 (24.2 % vs. 1.6%). As expected, the Census data show that there is a significantly positive relationship between education and income.
