As the looming US Presidential election seems likely to be fought at least in part over the issue of immigration, a new statistical analysis on migrants in America has emerged.

The Washington-based think tank, the Pew Research Centre, has aggregated the latest data on migrants in the US in a new report which paints a picture of an increasingly diverse society.

The foreign-born population of the US reached a record 44.8 million in 2018, or 13.7 per cent of the population, in 2018, the Pew Centre says.

The migrant population has more than quadrupled since the 1960s, and the number of migrants living in the US is projected to almost double by 2065.

“The age structure of the US immigrant population has changed alongside the changing immigrant origin regions,” the Pew reports says.

“As the largest group of immigrants shifted from Europeans, Canadians and other North Americans to Mexicans, the largest age group moved from ages 65-69 in 1960 to ages 40-44 in 2018.

“Today, European, Canadian and other North American immigrants tend to be older, with a median age of 53 and 54 respectively in 2018. Mexican immigrants are among the youngest, with a median age of 43. The age distribution of the US-born population has also transformed.

“In 1960, towards the end of the Baby Boom, the population was younger than in 2018, when these age groups were much more evenly dispersed,” the report says.

It says the regions migrants to the US have come from have dramatically shifted since the passage of the 1965 Immigration and Naturalization Act.

The report says in 1960, 84 per cent of migrants living in the US were born in Europe, Canada or other North American countries, while only 6 per cent were from Mexico, 4 per cent from Asia, 3 per cent from the rest of Latin America and 3 per cent from other areas.

Migrant origins in the US now differ drastically, with European, Canadian and other North American immigrants making up only a small share of the foreign-born population, at 13 per cent. Asians (28 per cent), Mexicans (25 per cent) and other Latin Americans (25 per cent) each make up about a quarter of the US migrant population, followed by 9 per cent who were born elsewhere the Pew report says.

And US migrant communities are more settled today than they were in 1990, when the share of those who had arrived within the past 10 years peaked at 44 per cent, the report says.

“Now, the amount of time that immigrants have spent in the US has grown. In 2018, 73 per cent of immigrants had lived in the U.S. for over 10 years, up from 56 per cent in 1990 (but similar to the share in 1970.)” the report says

“Starting as early as 2010, more Asian immigrants than Hispanic immigrants have arrived annually in the US, a reversal of historical trends. In the early 2000s, the number of newly arrived Hispanic immigrants greatly outnumbered newly arrived Asian immigrants,” it said.

Around the time of the Great Recession, Latin American immigration declined sharply, especially from Mexico.

The report says that the US-born children of immigrants (second generation Americans) make up 12 per cent of the nation’s population.

By 2050, immigrants and their children could account for 19 per cent and 18 per cent of the population, respectively, according to Pew Centre projections.

Since 1980, the share of migrants to the US who are proficient in English has declined, though it has increased slightly in recent years, the report said.

This decline, it says, has been driven entirely by those who speak only English at home, which fell from 30 per cent of immigrants ages 5 and older in 1980 to 17 per cent in 2018.

 The share who speak English “very well,” meanwhile, has increased slightly, from 27 per cent to 37 per cent over the same time period.

Among US migrants, Spanish is by far the most spoken non-English language with 42 per cent of migrants saying they speak Spanish at home, the report says.

But also around 6 per cent of migrants speak Chinese (including Mandarin and Cantonese), 5 per cent speak Hindi or a related language, 4 per cent speak Filipino or Tagalog, 3 per cent speak Vietnamese, 3 per cent speak French and 2 per cent speak Dravidian.

Education levels among US migrants have been steadily rising since the 1960s, along with the native-born population, the Pew report says.

“While there have been gains across the board, the increases have been most dramatic among immigrants from Asia, Europe and the Middle East and less so among those from Mexico and Central America,” the report says.

The US’ unauthorised migrant population grew rapidly between 1990 and 2007, reaching a peak of 12.2 million. Since then, the population declined to 10.5 million in 2017.

Unauthorised immigrants from Mexico make up less than half of all unauthorized immigrants and have been a driver of the group’s population decline – the number of unauthorized immigrants from Mexico fell from a peak of 6.9 million in 2007 to 4.9 million in 2017, the Pew report says.

About a quarter of the US’ foreign-born population are unauthorized migrants, while the majority of the nation’s migrants are in the US legally. Naturalised citizens account for the largest portion of the foreign-born population at 45 per cent.