UNITED NATIONS (AP) — More than 70% of the world’s people live in countries where inequality has grown since 1990, including China and India, and growing inequalities are benefiting the wealthiest, a U.N. report said Tuesday.

But increasing inequality is not a universal trend, the World Social Report 2020 added, saying there has been a decline in income inequality over the last two decades in most countries of Latin America and the Caribbean and in many African countries.

Despite this progress, the report said, the share of income going to the richest 1% of the global population increased in 46 out of 57 countries and areas for which data is available for 1990 to 2015.

In both developed and developing countries, tax rates declined, with the top income tax rates in developed countries dropping from 66% in 1981 to 43% in 2018, said the report by the U.N. Department of Economic and Social Affairs.

The income differences among some countries and regions also is dramatic. For example, the report said the average income of people living in North America is 16 times that of people living in sub-Saharan Africa.

“At a time when the consequences of our deeply unequal world play out in daily headlines, this report shows that the inequality challenge is a global one," U.N. chief economist Elliott Harris told reporters.

In the forward to the report, U.N. Secretary-General Antonio Guterres wrote, “In North and South alike, mass protests have flared up, fueled by a combination of economic woes, growing inequalities and job insecurity.”

“Income disparities and a lack of opportunities are creating a vicious cycle of inequality, frustration and discontent across generations,” he said.

The report, titled “Inequality in a Rapidly Changing World,” examines the effect of four trends on inequality: technological innovation, climate change, urbanization and international migration.

It said rapid technological breakthroughs in recent decades tend to create “winners and losers,” with highly skilled workers benefiting most and mainly low-skilled workers facing “job disruption — and, at times, destruction.”

Digital innovation and artificial intelligence are opening vast new employment opportunities in areas such as education, health and agriculture, but these can only be realized if everyone has access, the report said. This isn’t happening, so new “digital divides” are being created, it said.

The report cited one striking divide: about 87% of people in developed countries have Internet access, compared to just 19% in developing countries.

As for climate change, poorer countries in the tropics are among the most adversely affected and people there who are already living in poverty are being made even poorer, the report said.

If left unaddressed, it warned, climate change could cause millions of people to fall into poverty during the next 10 years. On the other side, it said, actions to combat climate change and transition to green economies can reduce poverty and inequality.

In a rapidly urbanizing world, the report said, the rural-urban divide is closing in some areas but widening in others.

“Cities are catalysts for economic growth, innovation and employment,” it said. “However, urban areas are more unequal than rural areas.”

While income is higher in cities compared to rural areas in most developed and developing countries, “one in four urban residents, or over one billion people, lived in slums” in 2016, it said.

The report called international migration “a powerful symbol of global inequality, whether in terms of wages, opportunities or lifestyles.”

It said the movement of millions of people across countries and continents every year “generally benefits most migrants and their countries of origin and destination,” though not evenly across countries or within countries.

Guterres said the report’s message is that these challenges are “not irreversible.” They can be “harnessed for a more equitable and sustainable world,” he said, “or they can be left to further divide us.”