A week after the conclusion of the Democratic national convention, Hillary Clinton is continuing to widen her advantage over Donald Trump, according to a pair of new national polls out Friday.

In a Wall Street Journal/NBC News poll, Clinton is up nine percentage points over Trump, with the Democratic nominee garnering 47 percent of support compared to Trump's 38 percent among registered voters nationwide.

With third-party candidates included, Clinton maintains her nine-point lead: forty-three percent to Trump's 34 percent, while Libertarian party nominee Gary Johnson has 10 percent, and the Green Party's Jill Stein has five percent.

A McClatchy/Marist poll shows a more dramatic 15-point lead for Clinton: the former secretary of state has 48 percent of support among voters nationwide, versus Trump's 33 percent.

Last month, Clinton was ahead by just three points: 42 to 39 percent.

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Third-party candidates made little difference in the McClatchy/Marist poll as well, with Clinton retaining a double-digit lead: forty-five percent to Trump's 31 percent. Johnson notches 10 percent with Stein at six percent.

Clinton's lead in both polls reflects growing support from two key demographic groups: white and male voters. White voters in the McClatchy/Marist survey, for instance, supported Clinton 41 percent to Trump's 39 percent.

Another poll by GenForward, conducted by the Black Youth Project at the University of Chicago, surveyed young voters to determine what they thought of the two presidential candidates.

Neither Trump nor Clinton is well-liked by young adults overall, with just 38 percent saying they have a favorable view of Clinton and even fewer -- 21 percent -- saying they have a favorable view of Trump.

On Clinton's email scandal, among all young adults in the GenForward poll, 43 percent say Clinton intentionally broke the law in her use of a personal server while she was secretary of state, and another 20 percent think she did so unintentionally.

As for the rest, 27 percent think she showed poor judgment but did not break the law, and 8 percent say she did nothing wrong at all.

More than half of young whites - 54 percent - think Clinton intentionally committed a crime, and another 17 percent think she did so unintentionally.

Young African-Americans, Asian-Americans and Hispanics view Clinton's actions in a more sympathetic light, though few clear her of all wrongdoing. Just 32 percent of Hispanics, 29 percent of Asian-Americans and 21 percent of African-Americans think Clinton intentionally broke the law, with most of the remainder saying she either did so unintentionally or showed poor judgment that did not amount to lawbreaking.

The WSJ/NBC survey was conducted from July 31 to August 3 among 800 registered voters. The poll had a 3.5 percent margin for error. The McClatchy/Marist survey of 1,132 adults was conducted August 1, with a margin of error of 2.9 percentage points. The GenForward poll of 1,940 adults age 18-30 was conducted July 9-20. The margin of error is 3.8 percentage points.