WASHINGTON (AP) -- This may be the year Congress decides what to do about the millions of immigrants living illegally in the U.S. And this may be the week when a bipartisan group of senators makes public details of the overhaul plan it has been negotiating for months.
But what will that be? Why now? And who are all these immigrants, once you get past the big round numbers?
A big dose of facts, figures and other information to help understand the current debate over immigration:
Major problems with U.S. immigration have been around for decades.
President George W. Bush tried to change the system and failed. President Barack Obama promised to overhaul it in his first term but never did.
In his second term, he's making immigration a priority, and Republicans also appear ready to deal.
Why the new commitment?
Obama won 71 percent of Hispanic voters in his 2012 re-election campaign, and he owes them. Last year's election also sent a loud message to Republicans that they can't ignore this pivotal voting bloc.
It's been the kind of breathtaking turnaround you rarely see in politics. Plus, there's growing pressure from business leaders, who want to make it easier for the U.S. to attract highly educated immigrants and to legally bring in more lower-skilled workers such as farm laborers.
WHAT'S THE PROBLEM?
Talk about "comprehensive immigration reform" generally centers on four main questions:
--What to do about the 11 million-plus immigrants who live in the U.S. without legal permission.
--How to tighten border security.
--How to keep businesses from employing people who are in the U.S. illegally.
--How to improve the legal immigration system, now so convoluted that the adjective "Byzantine" pops up all too frequently.
WHAT'S THE GANG OF EIGHT?
A group of four Democrats and four Republicans in the Senate, taking the lead in trying to craft legislation that would address all four questions.
Obama is preparing his own plan as a backup in case congressional talks fail. There's also a bipartisan House group working on draft legislation, but House Republican leaders may leave it to the Senate to make the first move.
COMING TO AMERICA
A record 40.4 million immigrants live in the U.S., representing 13 percent of the population. More than 18 million are naturalized citizens, 11 million are legal permanent or temporary residents, and more than 11 million are in the country without legal permission, according to the Pew Hispanic Center, a private research organization.
Those in the U.S. illegally made up about 3.7 percent of the U.S. population in 2010. While overall immigration has steadily grown, the number of immigrants in the U.S. illegally peaked at 12 million in 2007.
WE'RE NO. 1
The U.S. is the leading destination for immigrants. Russia's second, with 12.3 million, according to Pew.
Twenty-nine percent of the foreign-born in the U.S., or about 11.7 million people, came from Mexico. About 25 percent came from South and East Asia, 9 percent from the Caribbean, 8 percent from Central America, 7 percent South America, 4 percent the Middle East and the rest from elsewhere.
The figures are more lopsided for immigrants living here illegally: An estimated 58 percent are from Mexico. The next closest figure is 6 percent from El Salvador, says the government.
California has the largest share of the U.S. immigrant population, 27 percent, followed by New York, New Jersey, Florida, Nevada, Hawaii and Texas, according to the Migration Policy Institute, a private group focused on global immigration issues.
California has the largest share of immigrants in the U.S. illegally, at 25 percent, followed by Texas with 16 percent. Florida and New York each has 6 percent, and Georgia has 5 percent, according to the Department of Homeland Security.
Here's one way to think about the ways immigrants arrive in the U.S: Some come in the front door, others the side door and still others the back door, as laid out in a report from the private Population Reference Bureau.
--Arriving through the front door: people legally sponsored by their families or employers. Also refugees and asylum-seekers, and immigrants who win visas in an annual "diversity" lottery.
--Side door: legal temporary arrivals, including those who get visas to visit, work or study. There are dozens of types of nonimmigrant visas, available to people ranging from business visitors to foreign athletes and entertainers. Visitors from dozens of countries don't even need visas.