Democratic presidential nominee Hillary Clinton’s lead over Republican rival Donald Trump narrowed to less than 3 percentage points, according to a Reuters/Ipsos opinion poll released on Friday, down from nearly eight points on Monday.

About 42 percent of likely voters favored Clinton, to Trump’s 39 percent, according to the July 31-Aug. 4 online poll of 1,154 likely voters. The poll had a credibility interval of plus or minus 3 percentage points, meaning that the results suggest the race is roughly even.

Among registered voters over the same period, Clinton held a lead of five percentage points, down from eight percentage points on Monday, according to the poll.

The reasons behind the shift were unclear.