With 11 days to go before the US presidential election, Democratic nominee Hillary Clinton leads Republican Donald Trump by 15 percentage points among early voters surveyed in the past two weeks, according to the Reuters/Ipsos States of the Nation project.
Though data is not available for all early voting states, Clinton enjoys an edge in swing states such as Ohio and Arizona and in Republican Party strongholds such as Georgia and Texas.
An estimated 19 million Americans have voted so far in the election, according to the University of Florida's United States Election Project, accounting for as much as 20 per cent of the electorate.
Overall, Clinton remained on track to win a majority of votes in the Electoral College, the Reuters/Ipsos survey showed on Saturday.
Having so many ballots locked down before the November 8 election is good news for the Clinton campaign.
On Friday, the Federal Bureau of Investigation announced that it is examining newly discovered emails belonging to Clinton's close aide, Huma Abedin. Those emails were found on a computer belonging to Anthony Weiner, Abedin's estranged husband, during an unrelated investigation into illicit messages he is alleged to have sent to a teenage girl.
The Reuters/Ipsos survey was conducted before the news emerged on Friday afternoon.
It remains unclear whether the FBI inquiry will upset the balance in the race. The bureau disclosed nothing about the Abedin emails, including whether any of the messages were sent by or to Clinton.
Over the summer, the FBI said it was closing its investigation into Clinton's use of a private email system while secretary of state. Until Friday, her campaign seemed to have weathered the initial FBI email probe.
Clinton has held a lead averaging four to seven percentage points in polls in recent weeks as the Trump campaign wrestled with accusations by women of groping and other sexual advances. Trump has said none of the accusations are true. He also struggled in the recent presidential debates and faced questions about his taxes.
As of Thursday, Clinton's odds of receiving the 270 Electoral College votes needed to win the presidency remained at greater than 95 per cent, according to State of the Nation polling results released on Saturday. The project estimated she would win by 320 votes to 218, with 278 votes solidly for the Democrat.
Clinton's lead among early voters is similar to the lead enjoyed by President Barack Obama over Republican Mitt Romney at this point of the 2012 race, according to a Reuters/Ipsos poll taken at the time. Obama won the election by 332 electoral votes to Romney's 206.
Trump's path to a victory is narrow, and any realistic chance rests on his winning Ohio, North Carolina and Florida. As of Thursday, Ohio remained a toss-up. Florida and North Carolina were still tilting toward Clinton, according to the States of the Nation results.
The States of the Nation project is a survey of about 15,000 people every week in all 50 states plus Washington DC.