Democrat Hillary Clinton leads Republican Donald Trump by 8 percentage points in this week's NBC News/SurveyMonkey tracking poll for the general election. It is Clinton's largest lead in the survey since it began tracking the likely general election matchup in early May. UPI File Photos

WASHINGTON, June 28 (UPI) -- A tracking poll in the U.S. presidential election shows Democrat Hillary Clinton widening her lead over Republican Donald Trump and approaching the 50 percent threshold nationally in a head-to-head matchup.

The NBC News/SurveyMonkey online weekly tracking poll shows Clinton with a 49 percent-41 percent lead over Trump, her largest lead in that poll since it began tracking the likely general election matchup in early May.


Last week, Clinton held a lead of 6 percentage points.

On the issues, poll participants still ranked job creation and the economy as the most important, at 28 percent. In the two weeks since a nightclub shooting in Orlando killed 49 people, terrorism has ranked nearly 50 percent higher, with 21 percent of respondents now saying it's the most important issue.

President Barack Obama's approval rating ticked up one point to 52 percent, with 47 percent disapproval.

Both candidates' support drops when the survey includes two third-party candidates -- Gary Johnson, the Libertarian, and Jill Stein, of the Green Party -- as options.

Clinton still leads Trump, by 6 percentage points, 42 percent to 36 percent. Johnson is polling at 9 percent and Stein at 5 percent, with 7 percent giving no answer.

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Regardless of who they support, 57 percent of those surveyed said they believe Clinton will win the general election, a 21-point margin over those who believe Trump will win.

The Real Clear Politics polling average shows Clinton leading by 6.8 percentage points over Trump in a one-on-one matchup. A survey released Monday by ABC News and the Washington Post showed Clinton with a double-digit lead, 51 percent to 39 percent.

SurveyMonkey selected 6,556 adults age 18 or older from a pool of nearly 3 million people who answer surveys on its website. Of them, 5,818 were registered voters. Because the respondents initially self-select, no margin of error can be calculated.

NBC SurveyMonkey by United Press International