Former vice president Joe Biden took a double digit lead over Senator Bernie Sanders in one of the first polls conducted after Biden announced his bid for the presidency on Thursday.

Biden leads Sanders by 24 percentage points, an 11-point jump from the still sizable lead he held over the Vermont Democrat before making his presidential campaign official, according to a CNN poll released Tuesday.

About 39 percent of voters said they are leaning towards voting for Biden, compared to only 28 percent in March. Meanwhile, Sanders is at 15 percent among voters.

Of Democratic voters, almost half, 46 percent, said it is “extremely important” that the party’s nominee must be able to beat President Trump in 2020. Only 31 percent put that much emphasis on the candidate having the right experience to be president, and about 25 percent said it was very important that the nominee be willing to work on a bipartisan basis with his political opponents to accomplish his objectives.

However, almost two-thirds of likely Democratic voters, 64 percent, said it’s very possible they may still change their mind on their candidate preference.

The candidate tailing Biden and Sanders in the polls is South Bend, Indiana Mayor Pete Buttigieg at 11 percent, a six-point rise for him since last month. Senator Elizabeth Warren is currently behind him at 8 percent, former Texas Representative Beto O’Rourke sits at 6 percent and Senator Kamala Harris is at 5 percent.

The CNN/SRSS poll surveyed 1,007 likely Democratic voters between April 25 to 28 with a margin of error of 5.9 percentage points.