WASHINGTON (Reuters) - Latinos have long favored Democrats, but Republican presidential nominee Mitt Romney is on track to win over even fewer Hispanic voters than his party's other recent presidential contenders, according to a poll released on Thursday.
A Pew Research Center survey of registered Latino voters found that 21 percent backed Romney compared with 69 percent for President Barack Obama, who is seeking re-election in the tight November 6 contest.
That is 10 percentage points less than Republican nominee John McCain won four years ago and 19 percentage points less than former Republican President George W. Bush won in 2004. McCain of Arizona and Bush of Texas are from states with big Hispanic populations.
"A rising share of Latino voters say that the Democratic Party has more concern for Latinos than does the Republican Party," researchers at the nonpartisan group's Pew Hispanic Center wrote.
Overall, however, other polls show Romney extending his narrow lead over Obama following last week's debate.
More than 60 percent of Latinos said Democrats were more concerned for them, up from 45 percent last year, according to the poll, conducted from September 7 to October 4. Ten percent said Republicans had more concern for them, about the same as in 2011, it added.
Romney's lead ticked up slightly among Hispanics in the nine swing states that are seen as key to winning the election, such as Ohio and Florida. There he has 23 percent support from Hispanics compared to Obama's 65 percent.
In 2008, McCain won 31 percent of the Latino vote while Obama took 67 percent, other Pew data showed. Bush saw even greater support, winning about 40 percent of Latino voters in 2004, up from 34 percent in his 2000 victory.
While Hispanic support is increasingly important in U.S. elections, the poll showed much of the population likely will not vote.
Among the 1,765 Latino adults polled just over half - 903 - said they are registered to vote, and registered Latinos said they were less sure they would cast ballots in the election than other voters.
Seventy-seven percent said they were "absolutely certain" they would vote compared to 89 percent for all other registered voters, according to the poll, which has a margin of error rate of plus-or-minus 3.2 percentage points overall and 4.6 percentage points for the registered voters.
Despite the rise in states with laws requiring photo identification to vote, most of the registered Latinos said they were confident they had valid documentation needed to cast their ballots, Pew found.
Republicans generally back stricter controls against illegal immigration than Democrats, and in the Republican primaries to pick a nominee, Romney took a hard line, saying he supported what he called self-deportation for illegals.
But Obama's steady support among Latinos comes despite some discontent over his immigration policies.
Last month, the president said his "biggest failure" was the lack of comprehensive immigration reform, although his administration launched a program in June to allow young undocumented immigrants to apply for temporary work permits.
At the same time, however, deportations during his administration have hit record levels and include mostly Hispanics. An average of 400,000 people have been deported since Obama took office in 2009, Pew said, citing government data.
Nearly 90 percent of Latinos surveyed said they fully supported the new youth program compared to 63 percent of the general public, and many said they knew someone who had applied for the reprieve, Pew said.
About one in four Hispanics polled said they knew someone who had been deported or detained by federal authorities, the survey showed.
While white voters are still the majority, changing U.S. demographics and the rise of Latino and other ethnic minority births mean they will make up a greater share of the electorate in coming decades.
The number of eligible Hispanic voters increased 21.4 percent from 2004 to 2008, nearly five times the growth rate of eligible voters overall, Pew data show.
Today, nearly 24 million Hispanics are eligible to vote, the center said, and many of them are optimistic.
Like other voters, many said their finances have improved since 2011, the survey showed.
And while fewer than half said their financial situation is "excellent" or "good," about 70 percent of those registered to vote said they see their finances improving next year, it found.
Reporting By Susan Heavey; Editing by Vicki Allen