Short answers, pulled from the story.
In 1820, the ratio between the income of the top 20 percent of the world's population and the bottom 20 percent was a modest three to one.
Oxfam's 2021 report revealed that billionaires saw their wealth increase by $3.9 trillion while the number of people living on less than $5.50 a day likely increased by 500 million.
In 1863, Black people owned 0.5 percent of the US national wealth, and in 2019, it was just over 1.5 percent.
British researchers Richard G. Wilkinson and Kate Pickett have found higher rates of health and social problems, including obesity, mental illness, homicides, teenage births, and drug use, in countries and states with higher inequality.
Economists Emmanuel Saez and Thomas Piketty recommend much higher top marginal tax rates on the wealthy, up to 50 percent, 70 percent, or even 90 percent, to curb the concentration of wealth.