David M Jackson

USA TODAY

Hillary Clinton now leads Donald Trump by 8 percentage points among likely voters and 7 points among registered voters, according to a new Monmouth University Poll.

The poll finds the presumptive Democratic nominee leads Trump 49% to 41% among likely voters and 47% to 40% among registered voters.

The Monmouth poll also indicates that neither the Democratic candidate nor the presumptive GOP nominee are very popular — Clinton has a 52% unfavorable rating in the poll, while Trump has a 57% unfavorable rating.

“Clinton has the advantage as the general election campaign kicks off, particularly in key swing states," said Patrick Murray, director of the independent Monmouth University Polling Institute. "However, all signs point to 2016 turning out the most polarized electorate in memory."

Monmouth released the poll shortly after a major shake-up in the GOP campaign, as Trump dismissed campaign manager Corey Lewandowski.

Clinton's lead shrinks by a point when third-party candidates are included, Monmouth reported:

"When Libertarian nominee Gary Johnson and leading Green Party candidate Jill Stein are added to the mix, Clinton’s lead shrinks slightly to 6 points among registered voters – 42% to 36% for Trump, with Johnson earning 9% and Stein getting 4%. Clinton leads Trump by 7 points – 44% to 37% – among likely voters in this four-way contest."

Poll: Clinton 12 points ahead of Trump nationally

Elections 2016 | USA TODAY Network