Former Vice President Joe Biden has increased his margin as the front runner in the Democratic Presidential primary to double digit numbers over other competitors, according to a new CNN poll conducted by SRSS.

Biden has now 29% vote of Democratic supporters, which is 7 points up from the previous CNN survey conducted in last June. He has a 14-point lead over second placed Vermont Sen. Bernie Sanders who polled at 15% and 15 point lead over Massachusetts Sen. Elizabeth Warren who polled at 14%. Biden is the only candidate to have significantly gained after the previous polls, with the others largely remaining the same or slumping.

Senator Kamala Harris (D-Cal.) had the most notable decline in poll numbers as she went from 17% to 5%, equal to what her numbers were before the first debate. Harris had gained popularity after she managed to corner a lacklustre Biden during the first democratic debate on the issues of school busing, giving her a 12 point boost to 17% in the post-debate polls held in June.

The Democratic National congress will use the poll to determine which candidates qualify for the debate to be held in Houston in September, with former Housing and Urban Development Secretary Julian Castro becoming the 10th candidate to qualify after he hit 2% support.

The other candidates who have qualified along with Biden, Sander, Warren, Harris and Castro are South Bend Indiana Mayor Pete Buttigieg, Former Texas Congressman Beto O’Rourke, New Jersey Sen. Cory Booker and Minnesota Sen. Amy Klobuchar.

Billionaire businessman Tom Steyer, Hawaii Rep. Tulsi Gabbard and author Marianne Williamson have reached the fundraising threshold but still need more polls to qualify for the Houston debates next month. New York Sen. Kirsten Gillibrand hit 2% polls but has fallen short of the fundraising threshold.

Biden boasts the support of older voters, with 34% over 45 choosing the former Vice President, and conservative and moderate voters, with 34% of these people choosing him. The liberals however were in split in favor of Warren (23%), Biden (22%) and Sanders (22%).

In terms of ideology, 57% of moderate or conservative Democratic voters and 53% of liberal democratic voters seemed to agree that choosing a candidate who had a strong chance of beating President Donald Trump was more important than choosing a candidate who had the same views as them on major issues. Biden had the support of 35% voters in this group.

Warren still topped the list, when voters were asked which candidates they wanted to hear the most about with 20% votes (4% down from last time) followed by Harris with 18% votes, Sanders with 16% and  Biden with 15%.

The CNN poll conducted between 15 to 18 Aug. by SRSS, interviewed a random national sample of 1001 adults, with a sampling error of plus or minus 3.7 points. Biden’s lead comfortably falls outside the margin of error.