Final answer:
Stagnant wage rates and changes in family structure are major factors contributing to the rise in income inequality across households.
Step-by-step explanation:
The rise in income inequality across significant percentages of households can be attributed to several factors. One of the main factors is stagnant wage rates, where the wages of middle and lower-income workers have not kept up with inflation. Another factor is changes in family structure, such as the growth of single-parent families with lower incomes and two-career high-earner couples with higher incomes. These changes have contributed to approximately half of the rise in income inequality in recent decades.