Income inequality in USA

I wish to quote the following article from Wikipedia about income inequality in America, and explain in a separate article why it cause greater to people at the lower income level (compared to a society where the income distribution is more equal). I will also show the how Singapore fare in the Gini index, i.e. it is worse than America.

Quote from Wikipedia:
Income inequality is the extent to which income, most commonly measured by household or individual, is distributed in an uneven manner. While there seems to be consensus among social scientists that some degree of income inequality is needed, the extent of income inequality and its implications on society continue to be a subject of great debate, as they have been for over a century.

A study by the Southern Economic Journal found that "71 percent of American economists believe the distribution of income in the US should be more equal, and 81 percent feel that the redistribution of income is a legitimate role for government." 

Data from official sources indicate that income inequality has been increasing since the 1970s. As of 2006, the United States had one of the highest levels of income inequality, as measured through the Gini index, among the high income countries.

In 2010, the top 20% of Americans earned 49.4% of the nation’s income, compared with the 3.4% earned by the roughly 15% of the population living below the poverty line. This earnings ratio of 14.5 to 1 was an increase from the 13.6 to 1 ratio in 2008 and a significant rise from the historic low of 7.69 to 1 in 1968. 

Looking back even further to 1915, an era in which the Rockefellers and Carnegies dominated American industry, the richest 1% of Americans earned roughly 18% of all income. Today, the top 1% account for 24% of all income.