Pick a subject. It does not really matter which – income, life expectancy or the number of young men who will spend time in the criminal justice system.

Then compare the data for African Americans to that for white people. The results are nothing less than staggering.

Half a century after Martin Luther King was assassinated as he campaigned in support of striking sanitation workers in Memphis, and 55 years after he dared speak of his dream of the nation’s potential, the United States of America is a country where that ambition remains stalled.

Many experts say that is not because of chance or bad luck, but by design.

“Part of it is to do with the structural rules that have kept these iniquities present,” says Christina Greer, associate professor of political science at Fordham University in New York.

She says that when King was assassinated, he was campaigning not just for racial justice but for economic justice. Indeed, the name of the rally in Washington where he delivered his celebrated ‘dream speech’ was titled ‘March on Washington for Jobs and Freedom’.

Ms Greer says 50 years later African Americans are still struggling for economic equality and encountering the same issues that existed during the civil rights era: redlining (the denial of certain services because of an area someone lives in), the difficulty of getting loans and de facto segregation in many schools.

She says that for millions of Africans Americans it is not only more difficult to get jobs, but also harder to buy homes and also save wealth over generations.

Here are some of those numbers: life expectancy for African Americans is 75.6 years compared to 79 for whites. White households on average have 10 times more wealth than black households. In 2014, African Americans made up 34 per cent of the prison population, while constituting just 12 per cent of the total population.

Based on the Department of Justice’s own data, that means black people in the US are incarcerated at five times the rate of white people. An in-depth study by the Washington Post, tracking the number of fatal police shootings in the country, suggests American Americans are shot and killed by the police two-and-a-half times more often than white people.

In the field of education, while 52 per cent of African Americans have some sort of attendance at college compared to 59 per cent of white Americans, this falls to eight per and 12 per cent respectively for advanced degrees.

Another powerful statistic, in a nation that a year ago elected a president many believe has encouraged or given licence to racism and bigotry, is that a growing number of Americans – especially African Americans – believe racism is a big problem.

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A recent study by the Pew Research Centre found the number of Americans who say racism is a “big problem” in society has roughly doubled since 2011. While around 52 per cent of whites said this was the case, as many as 81 per cent of African Americans said it was a major issue.

“Martin Luther King was a heroic figure, but we forget too quickly how unpopular he was and how many powerful forces were trying to stop progress. King was murdered,” says Alondra Nelson, professor of sociology and gender studies at Columbia University.

She says many people had been “seduced” by the way King’s image had been transformed over the years. Yet at the time he was alive, the ideas he was fighting for – social, racial and economic justice – were utterly radical and enough to get him killed.

Ms Nelson says it is time for people to continue the fight and remember that “things can be lost as quickly as they are gained”.

Julene Allen, executive director and founder of Women For Action, an organisation that works with underrepresented women in Ohio and Illinois, says she believes after the passage of the Voting Rights Act and the Civil Rights Act people assumed progress would continue to be made. Yet history has shown nothing can be taken for granted.

“Racism is a mentality, and if you are stuck with that mentality we’re going to be still fighting that situation,” she says.